diff --git a/ydb/core/base/feature_flags.h b/ydb/core/base/feature_flags.h
index 262939d0fc0b..626ccad3f674 100644
--- a/ydb/core/base/feature_flags.h
+++ b/ydb/core/base/feature_flags.h
@@ -13,17 +13,6 @@ class TFeatureFlags: public NKikimrConfig::TFeatureFlags {
     using TBase::TBase;
     using TBase::operator=;
 
-    inline std::optional<bool> GetEnableMvcc() const {
-        switch (TBase::GetEnableMvcc()) {
-        case NKikimrConfig::TFeatureFlags::UNSET:
-            return std::nullopt;
-        case NKikimrConfig::TFeatureFlags::VALUE_TRUE:
-            return true;
-        case NKikimrConfig::TFeatureFlags::VALUE_FALSE:
-            return false;
-        }
-    }
-
     inline void SetEnableBackgroundCompactionForTest(bool value) {
         SetEnableBackgroundCompaction(value);
     }
diff --git a/ydb/core/kqp/executer_actor/kqp_data_executer.cpp b/ydb/core/kqp/executer_actor/kqp_data_executer.cpp
index 0b9674e3df88..2a4d9e7cfc42 100644
--- a/ydb/core/kqp/executer_actor/kqp_data_executer.cpp
+++ b/ydb/core/kqp/executer_actor/kqp_data_executer.cpp
@@ -182,8 +182,7 @@ class TKqpDataExecuter : public TKqpExecuterBase<TKqpDataExecuter, EExecType::Da
             !ImmediateTx &&
             !HasPersistentChannels &&
             !HasOlapTable &&
-            (!Database.empty() || AppData()->EnableMvccSnapshotWithLegacyDomainRoot) &&
-            AppData()->FeatureFlags.GetEnableMvccSnapshotReads()
+            (!Database.empty() || AppData()->EnableMvccSnapshotWithLegacyDomainRoot)
         );
 
         return forceSnapshot;
@@ -1272,6 +1271,11 @@ class TKqpDataExecuter : public TKqpExecuterBase<TKqpDataExecuter, EExecType::Da
                 LOG_N("Shard " << msg->TabletId << " lost pipe while waiting for reply"
                     << (msg->NotDelivered ? " (last message not delivered)" : ""));
 
+                if (ReadOnlyTx && msg->NotDelivered) {
+                    CancelProposal(msg->TabletId);
+                    return ReplyUnavailable(TStringBuilder() << "Could not deliver program to shard " << msg->TabletId);
+                }
+
                 return ReplyTxStateUnknown(msg->TabletId);
             }
 
diff --git a/ydb/core/kqp/session_actor/kqp_tx.cpp b/ydb/core/kqp/session_actor/kqp_tx.cpp
index ec5accc1b0e2..b419125c66be 100644
--- a/ydb/core/kqp/session_actor/kqp_tx.cpp
+++ b/ydb/core/kqp/session_actor/kqp_tx.cpp
@@ -123,10 +123,9 @@ TKqpTransactionInfo TKqpTransactionContext::GetInfo() const {
 bool NeedSnapshot(const TKqpTransactionContext& txCtx, const NYql::TKikimrConfiguration& config, bool rollbackTx,
     bool commitTx, const NKqpProto::TKqpPhyQuery& physicalQuery)
 {
-    if (*txCtx.EffectiveIsolationLevel != NKikimrKqp::ISOLATION_LEVEL_SERIALIZABLE)
-        return false;
+    Y_UNUSED(config);
 
-    if (!config.FeatureFlags.GetEnableMvccSnapshotReads())
+    if (*txCtx.EffectiveIsolationLevel != NKikimrKqp::ISOLATION_LEVEL_SERIALIZABLE)
         return false;
 
     if (txCtx.GetSnapshot().IsValid())
diff --git a/ydb/core/kqp/ut/common/kqp_ut_common.h b/ydb/core/kqp/ut/common/kqp_ut_common.h
index fce52247bd30..2f05c0d60834 100644
--- a/ydb/core/kqp/ut/common/kqp_ut_common.h
+++ b/ydb/core/kqp/ut/common/kqp_ut_common.h
@@ -178,10 +178,6 @@ class TKikimrRunner {
         return GetTestServer().GetRuntime()->WaitFuture(future);
     }
 
-    bool IsUsingSnapshotReads() const {
-        return Server->GetRuntime()->GetAppData().FeatureFlags.GetEnableMvccSnapshotReads();
-    }
-
 private:
     void Initialize(const TKikimrSettings& settings);
     void WaitForKqpProxyInit();
diff --git a/ydb/core/kqp/ut/opt/kqp_ne_ut.cpp b/ydb/core/kqp/ut/opt/kqp_ne_ut.cpp
index e9bd4c7eedcb..d79e0f3440a1 100644
--- a/ydb/core/kqp/ut/opt/kqp_ne_ut.cpp
+++ b/ydb/core/kqp/ut/opt/kqp_ne_ut.cpp
@@ -856,14 +856,7 @@ Y_UNIT_TEST_SUITE(KqpNewEngine) {
             SELECT * FROM `/Root/TwoShard` WHERE Key = 2;
         )", TTxControl::Tx(*tx).CommitTx()).GetValueSync();
 
-        if (kikimr.IsUsingSnapshotReads()) {
-            UNIT_ASSERT_VALUES_EQUAL_C(result.GetStatus(), EStatus::SUCCESS, result.GetIssues().ToString());
-        } else {
-            UNIT_ASSERT(!result.IsSuccess());
-            result.GetIssues().PrintTo(Cerr);
-            UNIT_ASSERT_VALUES_EQUAL(result.GetStatus(), EStatus::ABORTED);
-            UNIT_ASSERT(HasIssue(result.GetIssues(), NYql::TIssuesIds::KIKIMR_LOCKS_INVALIDATED));
-        }
+        UNIT_ASSERT_VALUES_EQUAL_C(result.GetStatus(), EStatus::SUCCESS, result.GetIssues().ToString());
     }
 
     Y_UNIT_TEST(LocksMultiShard) {
@@ -888,14 +881,7 @@ Y_UNIT_TEST_SUITE(KqpNewEngine) {
             SELECT * FROM `/Root/EightShard`;
         )", TTxControl::Tx(*tx).CommitTx()).GetValueSync();
 
-        if (kikimr.IsUsingSnapshotReads()) {
-            UNIT_ASSERT_VALUES_EQUAL_C(result.GetStatus(), EStatus::SUCCESS, result.GetIssues().ToString());
-        } else {
-            UNIT_ASSERT(!result.IsSuccess());
-            result.GetIssues().PrintTo(Cerr);
-            UNIT_ASSERT_VALUES_EQUAL(result.GetStatus(), EStatus::ABORTED);
-            UNIT_ASSERT(HasIssue(result.GetIssues(), NYql::TIssuesIds::KIKIMR_LOCKS_INVALIDATED));
-        }
+        UNIT_ASSERT_VALUES_EQUAL_C(result.GetStatus(), EStatus::SUCCESS, result.GetIssues().ToString());
     }
 
     Y_UNIT_TEST(LocksMultiShardOk) {
@@ -1016,13 +1002,7 @@ Y_UNIT_TEST_SUITE(KqpNewEngine) {
             SELECT 42;
         )", TTxControl::Tx(*tx).CommitTx()).GetValueSync();
 
-        if (kikimr.IsUsingSnapshotReads()) {
-            UNIT_ASSERT_VALUES_EQUAL_C(result.GetStatus(), EStatus::SUCCESS, result.GetIssues().ToString());
-        } else {
-            Cerr << result.GetIssues().ToString() << Endl;
-            UNIT_ASSERT_VALUES_EQUAL_C(result.GetStatus(), EStatus::ABORTED, result.GetIssues().ToString());
-            UNIT_ASSERT(HasIssue(result.GetIssues(), NYql::TIssuesIds::KIKIMR_LOCKS_INVALIDATED));
-        }
+        UNIT_ASSERT_VALUES_EQUAL_C(result.GetStatus(), EStatus::SUCCESS, result.GetIssues().ToString());
     }
 
     Y_UNIT_TEST(BrokenLocksAtROTxSharded) {
@@ -1050,13 +1030,7 @@ Y_UNIT_TEST_SUITE(KqpNewEngine) {
             SELECT 42;
         )", TTxControl::Tx(*tx).CommitTx()).GetValueSync();
 
-        if (kikimr.IsUsingSnapshotReads()) {
-            UNIT_ASSERT_VALUES_EQUAL_C(result.GetStatus(), EStatus::SUCCESS, result.GetIssues().ToString());
-        } else {
-            Cerr << result.GetIssues().ToString() << Endl;
-            UNIT_ASSERT_VALUES_EQUAL_C(result.GetStatus(), EStatus::ABORTED, result.GetIssues().ToString());
-            UNIT_ASSERT(HasIssue(result.GetIssues(), NYql::TIssuesIds::KIKIMR_LOCKS_INVALIDATED));
-        }
+        UNIT_ASSERT_VALUES_EQUAL_C(result.GetStatus(), EStatus::SUCCESS, result.GetIssues().ToString());
     }
 
     Y_UNIT_TEST(BrokenLocksOnUpdate) {
diff --git a/ydb/core/kqp/ut/tx/kqp_tx_ut.cpp b/ydb/core/kqp/ut/tx/kqp_tx_ut.cpp
index abc0c2ed2738..d9b77c2cf891 100644
--- a/ydb/core/kqp/ut/tx/kqp_tx_ut.cpp
+++ b/ydb/core/kqp/ut/tx/kqp_tx_ut.cpp
@@ -357,12 +357,7 @@ Y_UNIT_TEST_SUITE(KqpTx) {
         }
 
         auto commitResult = tx->Commit().ExtractValueSync();
-        if (kikimr.IsUsingSnapshotReads()) {
-            UNIT_ASSERT_VALUES_EQUAL_C(commitResult.GetStatus(), EStatus::SUCCESS, commitResult.GetIssues().ToString());
-        } else {
-            UNIT_ASSERT_VALUES_EQUAL_C(commitResult.GetStatus(), EStatus::ABORTED, commitResult.GetIssues().ToString());
-            UNIT_ASSERT(HasIssue(commitResult.GetIssues(), NYql::TIssuesIds::KIKIMR_LOCKS_INVALIDATED));
-        }
+        UNIT_ASSERT_VALUES_EQUAL_C(commitResult.GetStatus(), EStatus::SUCCESS, commitResult.GetIssues().ToString());
     }
 
     Y_UNIT_TEST(EmptyTxOnCommit) {
diff --git a/ydb/core/protos/config.proto b/ydb/core/protos/config.proto
index 62af1c8b2677..bb6323000edd 100644
--- a/ydb/core/protos/config.proto
+++ b/ydb/core/protos/config.proto
@@ -1112,13 +1112,14 @@ message TImmediateControlsConfig {
             MaxValue: 134217728,
             DefaultValue: 0 }];
 
+        // Note: these settings are deprecated (always enabled)
         optional uint64 PrioritizedMvccSnapshotReads = 8 [(ControlOptions) = {
-            Description: "Enables prioritized mvcc snapshot reads over immediate writes",
+            Description: "Enables prioritized mvcc snapshot reads over immediate writes (deprecated, always enabled)",
             MinValue: 0,
             MaxValue: 1,
             DefaultValue: 1 }];
         optional uint64 UnprotectedMvccSnapshotReads = 9 [(ControlOptions) = {
-            Description: "Enables unprotected (fully readonly) mvcc snapshot reads",
+            Description: "Enables unprotected (fully readonly) mvcc snapshot reads (deprecated, always enabled)",
             MinValue: 0,
             MaxValue: 1,
             DefaultValue: 1 }];
diff --git a/ydb/core/protos/feature_flags.proto b/ydb/core/protos/feature_flags.proto
index bf4af84de48b..79a55c2189b8 100644
--- a/ydb/core/protos/feature_flags.proto
+++ b/ydb/core/protos/feature_flags.proto
@@ -54,8 +54,8 @@ message TFeatureFlags {
     optional bool EnableKqpScanOverPersistentSnapshot = 43 [default = true]; // deprecated: always true
     optional bool EnableOlapSchemaOperations = 44 [default = true];
     optional bool EnableVPatch = 45 [default = true];
-    optional bool EnableMvccSnapshotReads = 46 [default = true];
-    optional Tribool EnableMvcc = 47 [default = VALUE_TRUE];
+    optional bool EnableMvccSnapshotReads = 46 [default = true]; // deprecated: always true
+    optional Tribool EnableMvcc = 47 [default = VALUE_TRUE]; // deprecated: always true
     optional bool EnableSchemeTransactionsAtSchemeShard = 48 [default = true];
     optional bool EnableArrowFormatAtDatashard = 49 [default = false];
     optional bool Enable3x3RequestsForMirror3DCMinLatencyPut = 50 [default = false];
diff --git a/ydb/core/testlib/basics/feature_flags.h b/ydb/core/testlib/basics/feature_flags.h
index 32b44d6c7193..94ebd910a20d 100644
--- a/ydb/core/testlib/basics/feature_flags.h
+++ b/ydb/core/testlib/basics/feature_flags.h
@@ -26,7 +26,6 @@ class TTestFeatureFlagsHolder {
     FEATURE_FLAG_SETTER(EnableDataColumnForIndexTable)
     FEATURE_FLAG_SETTER(EnableClockGettimeForUserCpuAccounting)
     FEATURE_FLAG_SETTER(EnableOlapSchemaOperations)
-    FEATURE_FLAG_SETTER(EnableMvccSnapshotReads)
     FEATURE_FLAG_SETTER(EnableBackgroundCompaction)
     FEATURE_FLAG_SETTER(EnableBackgroundCompactionServerless)
     FEATURE_FLAG_SETTER(EnableBorrowedSplitCompaction)
diff --git a/ydb/core/tx/datashard/datashard.cpp b/ydb/core/tx/datashard/datashard.cpp
index 6ac1352f8cfa..c251597f7ce7 100644
--- a/ydb/core/tx/datashard/datashard.cpp
+++ b/ydb/core/tx/datashard/datashard.cpp
@@ -151,8 +151,6 @@ TDataShard::TDataShard(const TActorId &tablet, TTabletStorageInfo *info)
     , BackupReadAheadHi(0, 0, 128*1024*1024)
     , TtlReadAheadLo(0, 0, 64*1024*1024)
     , TtlReadAheadHi(0, 0, 128*1024*1024)
-    , EnablePrioritizedMvccSnapshotReads(1, 0, 1)
-    , EnableUnprotectedMvccSnapshotReads(1, 0, 1)
     , EnableLockedWrites(1, 0, 1)
     , MaxLockedWritesPerKey(1000, 0, 1000000)
     , EnableLeaderLeases(1, 0, 1)
@@ -325,8 +323,6 @@ void TDataShard::IcbRegister() {
         appData->Icb->RegisterSharedControl(TtlReadAheadLo, "DataShardControls.TtlReadAheadLo");
         appData->Icb->RegisterSharedControl(TtlReadAheadHi, "DataShardControls.TtlReadAheadHi");
 
-        appData->Icb->RegisterSharedControl(EnablePrioritizedMvccSnapshotReads, "DataShardControls.PrioritizedMvccSnapshotReads");
-        appData->Icb->RegisterSharedControl(EnableUnprotectedMvccSnapshotReads, "DataShardControls.UnprotectedMvccSnapshotReads");
         appData->Icb->RegisterSharedControl(EnableLockedWrites, "DataShardControls.EnableLockedWrites");
         appData->Icb->RegisterSharedControl(MaxLockedWritesPerKey, "DataShardControls.MaxLockedWritesPerKey");
 
@@ -2098,27 +2094,20 @@ TDataShard::TPromotePostExecuteEdges TDataShard::PromoteImmediatePostExecuteEdge
             break;
 
         case EPromotePostExecuteEdges::RepeatableRead: {
-            bool unprotectedReads = GetEnableUnprotectedMvccSnapshotReads();
-            if (unprotectedReads) {
-                // We want to use unprotected reads, but we need to make sure it's properly marked first
-                if (!SnapshotManager.GetPerformedUnprotectedReads()) {
-                    SnapshotManager.SetPerformedUnprotectedReads(true, txc);
-                    res.HadWrites = true;
-                }
-                if (!res.HadWrites && !SnapshotManager.IsPerformedUnprotectedReadsCommitted()) {
-                    // We need to wait for completion until the flag is committed
-                    res.WaitCompletion = true;
-                }
-                SnapshotManager.PromoteUnprotectedReadEdge(version);
-            } else if (SnapshotManager.GetPerformedUnprotectedReads()) {
-                // We want to drop the flag as soon as possible
-                SnapshotManager.SetPerformedUnprotectedReads(false, txc);
+            // We want to use unprotected reads, but we need to make sure it's properly marked first
+            if (!SnapshotManager.GetPerformedUnprotectedReads()) {
+                SnapshotManager.SetPerformedUnprotectedReads(true, txc);
                 res.HadWrites = true;
             }
+            if (!res.HadWrites && !SnapshotManager.IsPerformedUnprotectedReadsCommitted()) {
+                // We need to wait for completion until the flag is committed
+                res.WaitCompletion = true;
+            }
+            SnapshotManager.PromoteUnprotectedReadEdge(version);
 
             // We want to promote the complete edge when protected reads are
             // used or when we're already writing something anyway.
-            if (res.HadWrites || !unprotectedReads) {
+            if (res.HadWrites) {
                 res.HadWrites |= SnapshotManager.PromoteCompleteEdge(version, txc);
                 if (!res.HadWrites && SnapshotManager.GetCommittedCompleteEdge() < version) {
                     // We need to wait for completion because some other transaction
@@ -3333,7 +3322,7 @@ bool TDataShard::CheckTxNeedWait(const TEvDataShard::TEvProposeTransaction::TPtr
     auto& rec = msg->Record;
     if (rec.HasMvccSnapshot()) {
         TRowVersion rowVersion(rec.GetMvccSnapshot().GetStep(), rec.GetMvccSnapshot().GetTxId());
-        TRowVersion unreadableEdge = Pipeline.GetUnreadableEdge(GetEnablePrioritizedMvccSnapshotReads());
+        TRowVersion unreadableEdge = Pipeline.GetUnreadableEdge();
         if (rowVersion >= unreadableEdge) {
             LOG_TRACE_S(*TlsActivationContext, NKikimrServices::TX_DATASHARD, "New transaction reads from " << rowVersion << " which is not before unreadable edge " << unreadableEdge);
             LWTRACK(ProposeTransactionWaitSnapshot, msg->Orbit, rowVersion.Step, rowVersion.TxId);
diff --git a/ydb/core/tx/datashard/datashard__init.cpp b/ydb/core/tx/datashard/datashard__init.cpp
index 065234b1f864..93fb4ce452a5 100644
--- a/ydb/core/tx/datashard/datashard__init.cpp
+++ b/ydb/core/tx/datashard/datashard__init.cpp
@@ -589,13 +589,11 @@ class TDataShard::TTxInitSchema : public TTransactionBase<TDataShard> {
 
             Self->PersistSys(db, Schema::Sys_State, Self->State);
 
-            if (AppData(ctx)->FeatureFlags.GetEnableMvcc()) {
-                auto state = *AppData(ctx)->FeatureFlags.GetEnableMvcc() ? EMvccState::MvccEnabled : EMvccState::MvccDisabled;
-                Self->PersistSys(db, Schema::SysMvcc_State, (ui32)state);
+            auto state = EMvccState::MvccEnabled;
+            Self->PersistSys(db, Schema::SysMvcc_State, (ui32)state);
 
-                LOG_DEBUG(ctx, NKikimrServices::TX_DATASHARD, TStringBuilder() << "TxInitSchema.Execute"
-                    << " MVCC state switched to" << (*AppData(ctx)->FeatureFlags.GetEnableMvcc() ? " enabled" : " disabled") << " state");
-            }
+            LOG_DEBUG(ctx, NKikimrServices::TX_DATASHARD, TStringBuilder() << "TxInitSchema.Execute"
+                << " MVCC state switched to  enabled state");
 
             Self->MvccSwitchState = TSwitchState::DONE;
         }
diff --git a/ydb/core/tx/datashard/datashard__read_iterator.cpp b/ydb/core/tx/datashard/datashard__read_iterator.cpp
index 8dca4a6ddc6b..80d3143ef83c 100644
--- a/ydb/core/tx/datashard/datashard__read_iterator.cpp
+++ b/ydb/core/tx/datashard/datashard__read_iterator.cpp
@@ -2026,8 +2026,7 @@ class TDataShard::TTxReadViaPipeline : public NTabletFlatExecutor::TTransactionB
                                     snapshotUnavailable = true;
                                 }
                             } else {
-                                auto prioritizedMvccSnapshotReads = Self->GetEnablePrioritizedMvccSnapshotReads();
-                                TRowVersion unreadableEdge = Self->Pipeline.GetUnreadableEdge(prioritizedMvccSnapshotReads);
+                                TRowVersion unreadableEdge = Self->Pipeline.GetUnreadableEdge();
                                 if (state.ReadVersion >= unreadableEdge) {
                                     LWTRACK(ReadWaitSnapshot, request->Orbit, state.ReadVersion.Step, state.ReadVersion.TxId);
                                     Self->Pipeline.AddWaitingReadIterator(state.ReadVersion, std::move(Ev), ctx);
diff --git a/ydb/core/tx/datashard/datashard_impl.h b/ydb/core/tx/datashard/datashard_impl.h
index c9becaedfcee..2d5ff957122f 100644
--- a/ydb/core/tx/datashard/datashard_impl.h
+++ b/ydb/core/tx/datashard/datashard_impl.h
@@ -1646,16 +1646,6 @@ class TDataShard
         return TtlReadAheadHi;
     }
 
-    bool GetEnablePrioritizedMvccSnapshotReads() const {
-        ui64 value = EnablePrioritizedMvccSnapshotReads;
-        return value != 0;
-    }
-
-    bool GetEnableUnprotectedMvccSnapshotReads() const {
-        ui64 value = EnableUnprotectedMvccSnapshotReads;
-        return value != 0;
-    }
-
     bool GetEnableLockedWrites() const {
         ui64 value = EnableLockedWrites;
         return value != 0;
@@ -2649,8 +2639,6 @@ class TDataShard
     TControlWrapper TtlReadAheadLo;
     TControlWrapper TtlReadAheadHi;
 
-    TControlWrapper EnablePrioritizedMvccSnapshotReads;
-    TControlWrapper EnableUnprotectedMvccSnapshotReads;
     TControlWrapper EnableLockedWrites;
     TControlWrapper MaxLockedWritesPerKey;
 
diff --git a/ydb/core/tx/datashard/datashard_pipeline.cpp b/ydb/core/tx/datashard/datashard_pipeline.cpp
index 8d8eec8f9d09..20e69bf2c762 100644
--- a/ydb/core/tx/datashard/datashard_pipeline.cpp
+++ b/ydb/core/tx/datashard/datashard_pipeline.cpp
@@ -1918,14 +1918,13 @@ bool TPipeline::AddWaitingTxOp(TEvDataShard::TEvProposeTransaction::TPtr& ev, co
     if (Self->MvccSwitchState == TSwitchState::SWITCHING) {
         WaitingDataTxOps.emplace(TRowVersion::Min(), IEventHandle::Upcast<TEvDataShard::TEvProposeTransaction>(std::move(ev)));  // postpone tx processing till mvcc state switch is finished
     } else {
-        bool prioritizedReads = Self->GetEnablePrioritizedMvccSnapshotReads();
         Y_DEBUG_ABORT_UNLESS(ev->Get()->Record.HasMvccSnapshot());
         TRowVersion snapshot(ev->Get()->Record.GetMvccSnapshot().GetStep(), ev->Get()->Record.GetMvccSnapshot().GetTxId());
         WaitingDataTxOps.emplace(snapshot, IEventHandle::Upcast<TEvDataShard::TEvProposeTransaction>(std::move(ev)));
-        const ui64 waitStep = prioritizedReads ? snapshot.Step : snapshot.Step + 1;
+        const ui64 waitStep = snapshot.Step;
         TRowVersion unreadableEdge;
-        if (!Self->WaitPlanStep(waitStep) && snapshot < (unreadableEdge = GetUnreadableEdge(prioritizedReads))) {
-            ActivateWaitingTxOps(unreadableEdge, prioritizedReads, ctx);  // Async MediatorTimeCastEntry update, need to reschedule the op
+        if (!Self->WaitPlanStep(waitStep) && snapshot < (unreadableEdge = GetUnreadableEdge())) {
+            ActivateWaitingTxOps(unreadableEdge, ctx);  // Async MediatorTimeCastEntry update, need to reschedule the op
         }
     }
 
@@ -1941,7 +1940,7 @@ bool TPipeline::AddWaitingTxOp(NEvents::TDataEvents::TEvWrite::TPtr& ev) {
     return true;
 }
 
-void TPipeline::ActivateWaitingTxOps(TRowVersion edge, bool prioritizedReads, const TActorContext& ctx) {
+void TPipeline::ActivateWaitingTxOps(TRowVersion edge, const TActorContext& ctx) {
     LOG_TRACE_S(ctx, NKikimrServices::TX_DATASHARD, Self->TabletID() << " ActivateWaitingTxOps for version# " << edge
         << ", txOps: " << (WaitingDataTxOps.empty() ? "empty" : ToString(WaitingDataTxOps.begin()->first.Step))
         << ", readIterators: "
@@ -1976,8 +1975,8 @@ void TPipeline::ActivateWaitingTxOps(TRowVersion edge, bool prioritizedReads, co
         }
 
         if (minWait == TRowVersion::Max() ||
-            Self->WaitPlanStep(prioritizedReads ? minWait.Step : minWait.Step + 1) ||
-            minWait >= (edge = GetUnreadableEdge(prioritizedReads)))
+            Self->WaitPlanStep(minWait.Step) ||
+            minWait >= (edge = GetUnreadableEdge()))
         {
             break;
         }
@@ -1995,8 +1994,7 @@ void TPipeline::ActivateWaitingTxOps(const TActorContext& ctx) {
     if (isEmpty || Self->MvccSwitchState == TSwitchState::SWITCHING)
         return;
 
-    bool prioritizedReads = Self->GetEnablePrioritizedMvccSnapshotReads();
-    ActivateWaitingTxOps(GetUnreadableEdge(prioritizedReads), prioritizedReads, ctx);
+    ActivateWaitingTxOps(GetUnreadableEdge(), ctx);
 }
 
 void TPipeline::AddWaitingReadIterator(
@@ -2016,12 +2014,11 @@ void TPipeline::AddWaitingReadIterator(
     auto readId = ev->Get()->Record.GetReadId();
     WaitingDataReadIterators.emplace(version, std::move(ev));
 
-    bool prioritizedReads = Self->GetEnablePrioritizedMvccSnapshotReads();
-    const ui64 waitStep = prioritizedReads ? version.Step : version.Step + 1;
+    const ui64 waitStep = version.Step;
     TRowVersion unreadableEdge = TRowVersion::Min();
-    if (!Self->WaitPlanStep(waitStep) && version < (unreadableEdge = GetUnreadableEdge(prioritizedReads))) {
+    if (!Self->WaitPlanStep(waitStep) && version < (unreadableEdge = GetUnreadableEdge())) {
         // Async MediatorTimeCastEntry update, need to reschedule transaction
-        ActivateWaitingTxOps(unreadableEdge, prioritizedReads, ctx);
+        ActivateWaitingTxOps(unreadableEdge, ctx);
     }
 
     LOG_TRACE_S(ctx, NKikimrServices::TX_DATASHARD, Self->TabletID() << " put read iterator# " << readId
@@ -2075,7 +2072,7 @@ TRowVersion TPipeline::GetReadEdge() const {
     return TRowVersion(step, Max<ui64>());
 }
 
-TRowVersion TPipeline::GetUnreadableEdge(bool prioritizeReads) const {
+TRowVersion TPipeline::GetUnreadableEdge() const {
     const auto last = TRowVersion(
         GetLastActivePlannedOpStep(),
         GetLastActivePlannedOpId());
@@ -2109,17 +2106,10 @@ TRowVersion TPipeline::GetUnreadableEdge(bool prioritizeReads) const {
     // distributed transactions up to the end of that step.
     const TRowVersion mediatorEdge(mediatorStep, ::Max<ui64>());
 
-    if (prioritizeReads) {
-        // We are prioritizing reads, and we are ok with blocking immediate writes
-        // in the current step. So the first unreadable version is actually in
-        // the next step.
-        return mediatorEdge.Next();
-    } else {
-        // We cannot block immediate writes up to this edge, thus we actually
-        // need to wait until the edge progresses above this version. This
-        // would happen when mediator timecast moves to the next step.
-        return mediatorEdge;
-    }
+    // We are prioritizing reads, and we are ok with blocking immediate writes
+    // in the current step. So the first unreadable version is actually in
+    // the next step.
+    return mediatorEdge.Next();
 }
 
 void TPipeline::AddCompletingOp(const TOperation::TPtr& op) {
diff --git a/ydb/core/tx/datashard/datashard_pipeline.h b/ydb/core/tx/datashard/datashard_pipeline.h
index 86095eb04496..ed06f2c0362c 100644
--- a/ydb/core/tx/datashard/datashard_pipeline.h
+++ b/ydb/core/tx/datashard/datashard_pipeline.h
@@ -352,7 +352,7 @@ class TPipeline : TNonCopyable {
     bool CheckInflightLimit() const;
     bool AddWaitingTxOp(TEvDataShard::TEvProposeTransaction::TPtr& ev, const TActorContext& ctx);
     bool AddWaitingTxOp(NEvents::TDataEvents::TEvWrite::TPtr& ev);
-    void ActivateWaitingTxOps(TRowVersion edge, bool prioritizedReads, const TActorContext& ctx);
+    void ActivateWaitingTxOps(TRowVersion edge, const TActorContext& ctx);
     void ActivateWaitingTxOps(const TActorContext& ctx);
 
     ui64 WaitingReadIterators() const { return WaitingDataReadIterators.size(); }
@@ -366,7 +366,7 @@ class TPipeline : TNonCopyable {
     bool HandleWaitingReadIterator(const TReadIteratorId& readId, TEvDataShard::TEvRead* event);
 
     TRowVersion GetReadEdge() const;
-    TRowVersion GetUnreadableEdge(bool prioritizedReads) const;
+    TRowVersion GetUnreadableEdge() const;
 
     void AddCompletingOp(const TOperation::TPtr& op);
     void RemoveCompletingOp(const TOperation::TPtr& op);
diff --git a/ydb/core/tx/datashard/datashard_switch_mvcc_state.cpp b/ydb/core/tx/datashard/datashard_switch_mvcc_state.cpp
index 289250bf52a8..9bd42ebe7fad 100644
--- a/ydb/core/tx/datashard/datashard_switch_mvcc_state.cpp
+++ b/ydb/core/tx/datashard/datashard_switch_mvcc_state.cpp
@@ -15,8 +15,8 @@ void TDataShard::CheckMvccStateChangeCanStart(const TActorContext& ctx) {
 
                 case TShardState::Ready:
                 case TShardState::Frozen: {
-                    const auto enable = AppData(ctx)->FeatureFlags.GetEnableMvcc();
-                    if (enable && *enable != IsMvccEnabled()) {
+                    if (!IsMvccEnabled()) {
+                        // Force enable mvcc for potential old shards
                         MvccSwitchState = TSwitchState::SWITCHING;
                     } else {
                         MvccSwitchState = TSwitchState::DONE;
@@ -80,11 +80,10 @@ bool TDataShard::TTxExecuteMvccStateChange::Execute(TTransactionContext& txc, co
         Y_ABORT_UNLESS(Self->TxInFly() == 0 && Self->ImmediateInFly() == 0);
 
         auto [step, txId] = Self->LastCompleteTxVersion();
-        Self->SnapshotManager.ChangeMvccState(step, txId, txc,
-            *AppData(ctx)->FeatureFlags.GetEnableMvcc() ? EMvccState::MvccEnabled : EMvccState::MvccDisabled);
+        Self->SnapshotManager.ChangeMvccState(step, txId, txc, EMvccState::MvccEnabled);
 
         LOG_DEBUG(ctx, NKikimrServices::TX_DATASHARD, TStringBuilder() << "TTxExecuteMvccStateChange.Execute"
-            << " MVCC state switched to" << (*AppData(ctx)->FeatureFlags.GetEnableMvcc() ? " enabled" : " disabled") << " state");
+            << " MVCC state switched to enabled state");
 
         ActivateWaitingOps = true;
     }
diff --git a/ydb/core/tx/datashard/datashard_ut_kqp_errors.cpp b/ydb/core/tx/datashard/datashard_ut_kqp_errors.cpp
index cb13af2aac62..3ef5e85fba60 100644
--- a/ydb/core/tx/datashard/datashard_ut_kqp_errors.cpp
+++ b/ydb/core/tx/datashard/datashard_ut_kqp_errors.cpp
@@ -34,14 +34,11 @@ bool HasIssue(const TIssues& issues, ui32 code, TStringBuf message, std::functio
 
 class TLocalFixture {
 public:
-    TLocalFixture(bool disableSnaphots = false) {
+    TLocalFixture() {
         TPortManager pm;
         NKikimrConfig::TAppConfig app;
         app.MutableTableServiceConfig()->SetEnableKqpDataQuerySourceRead(false);
         TServerSettings serverSettings(pm.GetPort(2134));
-        if (disableSnaphots) {
-            serverSettings.SetEnableMvccSnapshotReads(false);
-        }
         serverSettings.SetDomainName("Root")
             .SetNodeCount(2)
             .SetUseRealThreads(false)
@@ -229,7 +226,7 @@ Y_UNIT_TEST(ProposeError) {
 }
 
 Y_UNIT_TEST(ProposeRequestUndelivered) {
-    TLocalFixture fixture(true);
+    TLocalFixture fixture;
     auto mitm = [&](TAutoPtr<IEventHandle> &ev) {
         if (ev->GetTypeRewrite() == TEvPipeCache::TEvForward::EventType) {
             auto forwardEvent = ev.Get()->Get<TEvPipeCache::TEvForward>();
@@ -301,24 +298,6 @@ void TestProposeResultLost(TTestActorRuntime& runtime, TActorId client, const TS
     fn(record);
 }
 
-Y_UNIT_TEST(ProposeResultLost_RoTx) {
-    TLocalFixture fixture(true);
-    TestProposeResultLost(*fixture.Runtime, fixture.Client,
-        Q_("select * from `/Root/table-1`"),
-        [](const NKikimrKqp::TEvQueryResponse& record) {
-            UNIT_ASSERT_VALUES_EQUAL_C(record.GetYdbStatus(), Ydb::StatusIds::UNAVAILABLE, record.DebugString());
-
-            TIssues issues;
-            IssuesFromMessage(record.GetResponse().GetQueryIssues(), issues);
-            UNIT_ASSERT_C(HasIssue(issues, NYql::TIssuesIds::KIKIMR_TEMPORARILY_UNAVAILABLE,
-                "Kikimr cluster or one of its subsystems was unavailable."), record.GetResponse().DebugString());
-
-            UNIT_ASSERT_C(HasIssue(issues, NKikimrIssues::TIssuesIds::TX_STATE_UNKNOWN, "", [] (const TIssue& issue) {
-                return issue.GetMessage().StartsWith("Tx state unknown for shard ");
-            }), record.GetResponse().DebugString());
-        });
-}
-
 Y_UNIT_TEST(ProposeResultLost_RwTx) {
     TLocalFixture fixture;
     TestProposeResultLost(*fixture.Runtime, fixture.Client,
diff --git a/ydb/core/tx/datashard/datashard_ut_minstep.cpp b/ydb/core/tx/datashard/datashard_ut_minstep.cpp
index c97617bb4e7e..ac7c6d280415 100644
--- a/ydb/core/tx/datashard/datashard_ut_minstep.cpp
+++ b/ydb/core/tx/datashard/datashard_ut_minstep.cpp
@@ -66,14 +66,11 @@ TAutoPtr<IEventHandle> EjectDataPropose(TServer::TPtr server, ui64 dataShard)
 }
 
 Y_UNIT_TEST_SUITE(TDataShardMinStepTest) {
-    void TestDropTablePlanComesNotTooEarly(const TString& query, Ydb::StatusIds::StatusCode expectedStatus, bool disableSnaphots = true) {
+    void TestDropTablePlanComesNotTooEarly(const TString& query, Ydb::StatusIds::StatusCode expectedStatus) {
         TPortManager pm;
         NKikimrConfig::TAppConfig app;
         app.MutableTableServiceConfig()->SetEnableKqpDataQuerySourceRead(false);
         TServerSettings serverSettings(pm.GetPort(2134));
-        if (disableSnaphots) {
-            serverSettings.SetEnableMvccSnapshotReads(false);
-        }
         serverSettings.SetDomainName("Root")
             .SetUseRealThreads(false)
             .SetAppConfig(app);
@@ -140,13 +137,6 @@ Y_UNIT_TEST_SUITE(TDataShardMinStepTest) {
         WaitTabletBecomesOffline(server, shard2);
     }
 
-    Y_UNIT_TEST(TestDropTablePlanComesNotTooEarlyRO) {
-        TestDropTablePlanComesNotTooEarly(
-            "SELECT * FROM `/Root/table-1`; SELECT * FROM `/Root/table-2`;",
-            Ydb::StatusIds::UNAVAILABLE
-        );
-    }
-
     Y_UNIT_TEST(TestDropTablePlanComesNotTooEarlyRW) {
         TestDropTablePlanComesNotTooEarly(
             "UPSERT INTO `/Root/table-2` (key, value) SELECT key, value FROM `/Root/table-1`;",
@@ -383,14 +373,11 @@ Y_UNIT_TEST_SUITE(TDataShardMinStepTest) {
         TestAlterProposeRebootMinStep(ERebootOnPropose::SchemeShard);
     }
 
-    void TestDropTableCompletesQuickly(const TString& query, Ydb::StatusIds::StatusCode expectedStatus, bool disableSnaphots = false) {
+    void TestDropTableCompletesQuickly(const TString& query, Ydb::StatusIds::StatusCode expectedStatus) {
         TPortManager pm;
         NKikimrConfig::TAppConfig app;
         app.MutableTableServiceConfig()->SetEnableKqpDataQuerySourceRead(false);
         TServerSettings serverSettings(pm.GetPort(2134));
-        if (disableSnaphots) {
-            serverSettings.SetEnableMvccSnapshotReads(false);
-        }
         serverSettings.SetDomainName("Root")
             .SetUseRealThreads(false)
             .SetAppConfig(app);
@@ -483,14 +470,6 @@ Y_UNIT_TEST_SUITE(TDataShardMinStepTest) {
         WaitTabletBecomesOffline(server, shard2);
     }
 
-    Y_UNIT_TEST(TestDropTableCompletesQuicklyRO) {
-        TestDropTableCompletesQuickly(
-            "SELECT * FROM `/Root/table-1` UNION ALL SELECT * FROM `/Root/table-2`;",
-            Ydb::StatusIds::SUCCESS,
-            true
-        );
-    }
-
     Y_UNIT_TEST(TestDropTableCompletesQuicklyRW) {
         TestDropTableCompletesQuickly(
             "UPSERT INTO `/Root/table-2` (key, value) SELECT key, value FROM `/Root/table-1`;",
diff --git a/ydb/core/tx/datashard/datashard_ut_order.cpp b/ydb/core/tx/datashard/datashard_ut_order.cpp
index 334084d1a4ab..194f826743e6 100644
--- a/ydb/core/tx/datashard/datashard_ut_order.cpp
+++ b/ydb/core/tx/datashard/datashard_ut_order.cpp
@@ -1313,95 +1313,6 @@ Y_UNIT_TEST(TestDelayedTxWaitsForWriteActiveTxOnly) {
     }
 }
 
-Y_UNIT_TEST(TestOnlyDataTxLagCausesRejects) {
-    TPortManager pm;
-    NKikimrConfig::TAppConfig app;
-    app.MutableTableServiceConfig()->SetEnableKqpDataQuerySourceRead(false);
-    TServerSettings serverSettings(pm.GetPort(2134));
-    serverSettings.SetEnableMvccSnapshotReads(false);
-    serverSettings.SetDomainName("Root")
-        .SetUseRealThreads(false)
-        .SetAppConfig(app)
-        // Note: this test currently relies on distributed non-mvcc reads,
-        // which are deprecated. This test should probably be removed.
-        .SetEnableDataShardVolatileTransactions(false);
-
-    Tests::TServer::TPtr server = new TServer(serverSettings);
-    auto &runtime = *server->GetRuntime();
-    auto sender = runtime.AllocateEdgeActor();
-    TAutoPtr<IEventHandle> handle;
-
-    runtime.SetLogPriority(NKikimrServices::TX_DATASHARD, NLog::PRI_TRACE);
-    runtime.SetLogPriority(NKikimrServices::KQP_EXECUTER, NLog::PRI_DEBUG);
-    runtime.SetLogPriority(NKikimrServices::KQP_SESSION, NLog::PRI_DEBUG);
-    runtime.SetLogPriority(NKikimrServices::MINIKQL_ENGINE, NActors::NLog::PRI_DEBUG);
-
-    const bool usesVolatileTxs = runtime.GetAppData(0).FeatureFlags.GetEnableDataShardVolatileTransactions();
-
-    InitRoot(server, sender);
-
-    CreateShardedTable(server, sender, "/Root", "table-1", 2);
-    //auto shards = GetTableShards(server, sender, "/Root/table-1");
-
-    ExecSQL(server, sender, Q_("UPSERT INTO `/Root/table-1` (key, value) VALUES (1, 3000000001), (3000000003, 3)"));
-
-    // Send ReadTable requests and wait until they hang waiting for quota.
-    for (int i = 0; i < 2; ++i) {
-        auto *req = new TEvTxUserProxy::TEvProposeTransaction;
-        req->Record.SetStreamResponse(true);
-        auto &tx = *req->Record.MutableTransaction()->MutableReadTableTransaction();
-        tx.SetPath("/Root/table-1");
-        runtime.Send(new IEventHandle(MakeTxProxyID(), sender, req));
-        runtime.GrabEdgeEventRethrow<TEvTxProcessing::TEvStreamQuotaRequest>(handle);
-    }
-
-    // Now move time forward and check we can still execute data txs.
-    runtime.UpdateCurrentTime(runtime.GetCurrentTime() + TDuration::Minutes(10));
-    // Wait for mediator timecast.
-    {
-        TDispatchOptions options;
-        options.FinalEvents.emplace_back(TEvMediatorTimecast::EvUpdate, 1);
-        runtime.DispatchEvents(options);
-    }
-
-    ExecSQL(server, sender, Q_("SELECT COUNT(*) FROM `/Root/table-1`"));
-
-    // Send SQL request which should hang due to lost RS.
-    TVector<THolder<IEventHandle>> readSets;
-    auto captureRS = [&](TAutoPtr<IEventHandle> &event) -> auto {
-        if (event->GetTypeRewrite() == TEvTxProcessing::EvReadSet) {
-            readSets.push_back(std::move(event));
-            return TTestActorRuntime::EEventAction::DROP;
-        }
-        return TTestActorRuntime::EEventAction::PROCESS;
-    };
-    runtime.SetObserverFunc(captureRS);
-
-    SendSQL(server, sender, Q_("UPSERT INTO `/Root/table-1` (key, value) SELECT value, key FROM `/Root/table-1`"));
-
-    const size_t expectedReadSets = usesVolatileTxs ? 4 : 2;
-    {
-        TDispatchOptions options;
-        options.FinalEvents.emplace_back(
-            [&](IEventHandle &) -> bool {
-                return readSets.size() >= expectedReadSets;
-            });
-        runtime.DispatchEvents(options);
-        UNIT_ASSERT_VALUES_EQUAL(readSets.size(), expectedReadSets);
-    }
-
-    // Now move time forward and check we can still execute data txs.
-    runtime.UpdateCurrentTime(runtime.GetCurrentTime() + TDuration::Minutes(10));
-    // Wait for mediator timecast.
-    {
-        TDispatchOptions options;
-        options.FinalEvents.emplace_back(TEvMediatorTimecast::EvUpdate, 1);
-        runtime.DispatchEvents(options);
-    }
-
-    ExecSQL(server, sender, Q_("SELECT COUNT(*) FROM `/Root/table-1`"), true, Ydb::StatusIds::OVERLOADED);
-}
-
 }
 
 Y_UNIT_TEST_SUITE(DataShardOutOfOrder) {
@@ -1535,143 +1446,6 @@ Y_UNIT_TEST_TWIN(TestOutOfOrderLockLost, StreamLookup) {
     }
 }
 
-Y_UNIT_TEST(TestMvccReadDoesntBlockWrites) {
-    TPortManager pm;
-    NKikimrConfig::TAppConfig app;
-    app.MutableTableServiceConfig()->SetEnableKqpDataQuerySourceRead(false);
-    app.MutableTableServiceConfig()->SetEnableKqpDataQueryStreamLookup(false);
-    TServerSettings serverSettings(pm.GetPort(2134));
-    serverSettings.SetEnableMvccSnapshotReads(false);
-    serverSettings.SetDomainName("Root")
-        .SetAppConfig(app)
-        .SetUseRealThreads(false);
-
-    Tests::TServer::TPtr server = new TServer(serverSettings);
-    auto &runtime = *server->GetRuntime();
-
-    auto sender = runtime.AllocateEdgeActor();
-
-    runtime.SetLogPriority(NKikimrServices::TX_DATASHARD, NLog::PRI_TRACE);
-    runtime.SetLogPriority(NKikimrServices::KQP_EXECUTER, NLog::PRI_DEBUG);
-
-    const bool usesVolatileTxs = runtime.GetAppData(0).FeatureFlags.GetEnableDataShardVolatileTransactions();
-
-    InitRoot(server, sender);
-
-    CreateShardedTable(server, sender, "/Root", "table-1", 1);
-    CreateShardedTable(server, sender, "/Root", "table-2", 1);
-
-    ExecSQL(server, sender, Q_("UPSERT INTO `/Root/table-1` (key, value) VALUES (1, 1);"));
-    ExecSQL(server, sender, Q_("UPSERT INTO `/Root/table-2` (key, value) VALUES (2, 2);"));
-
-    TString sessionId = CreateSessionRPC(runtime);
-    TString simpleSession = CreateSessionRPC(runtime);
-
-    TString txId;
-    {
-        auto result = KqpSimpleBegin(runtime, sessionId, txId, Q_(R"(
-            SELECT * FROM `/Root/table-1`
-            UNION ALL
-            SELECT * FROM `/Root/table-2`
-            ORDER BY key)"));
-        UNIT_ASSERT_VALUES_EQUAL(
-            result,
-            "{ items { uint32_value: 1 } items { uint32_value: 1 } }, "
-            "{ items { uint32_value: 2 } items { uint32_value: 2 } }");
-    }
-
-    // Capture and block all readset messages
-    TVector<THolder<IEventHandle>> readSets;
-    auto captureRS = [&](TAutoPtr<IEventHandle> &event) -> auto {
-        if (event->GetTypeRewrite() == TEvTxProcessing::EvReadSet) {
-            readSets.push_back(std::move(event));
-            return TTestActorRuntime::EEventAction::DROP;
-        }
-        return TTestActorRuntime::EEventAction::PROCESS;
-    };
-    auto prevObserverFunc = runtime.SetObserverFunc(captureRS);
-
-    // Send a commit request, it would block on readset exchange
-    auto f2 = SendRequest(runtime, MakeSimpleRequestRPC(Q_(R"(
-        UPSERT INTO `/Root/table-1` (key, value) VALUES (3, 2);
-        UPSERT INTO `/Root/table-2` (key, value) VALUES (4, 2);)"), sessionId, txId, true));
-
-    // Wait until we captured both readsets
-    const size_t expectedReadSets = usesVolatileTxs ? 4 : 2;
-    {
-        TDispatchOptions options;
-        options.FinalEvents.emplace_back(
-            [&](IEventHandle &) -> bool {
-                return readSets.size() >= expectedReadSets;
-            });
-        runtime.DispatchEvents(options);
-        UNIT_ASSERT_VALUES_EQUAL(readSets.size(), expectedReadSets);
-    }
-    runtime.SetObserverFunc(prevObserverFunc);
-
-    // it will be blocked by previous transaction that is waiting for its readsets
-    auto simpleF = SendRequest(runtime, MakeSimpleRequestRPC(Q_(R"(
-        $rows = (
-            SELECT * FROM `/Root/table-1` WHERE key = 3 OR key = 5
-            UNION ALL
-            SELECT * FROM `/Root/table-2` WHERE key = 4 OR key = 6
-        );
-        SELECT key, value FROM $rows ORDER BY key)"), simpleSession, "", true));
-
-    // wait for the tx is planned
-    TDispatchOptions opts;
-    opts.FinalEvents.push_back(TDispatchOptions::TFinalEventCondition(TEvTxProcessing::EEv::EvPlanStep, 2));
-    runtime.DispatchEvents(opts);
-
-    {
-        // despite it's writing into the key that previous transaction reads this write should finish successfully
-        auto result = KqpSimpleExec(runtime, Q_(R"(
-            UPSERT INTO `/Root/table-1` (key, value) VALUES (5, 10);
-            UPSERT INTO `/Root/table-2` (key, value) VALUES (6, 10))"));
-        UNIT_ASSERT_VALUES_EQUAL(result, "<empty>");
-    }
-
-    // resend readsets, it will unblock both commit tx and read
-    for (auto& ev : readSets) {
-        runtime.Send(ev.Release(), 0, /* via actor system */ true);
-    }
-    readSets.clear();
-
-    // Read the commit reply next, it must succeed
-    {
-        auto response = AwaitResponse(runtime, f2);
-        UNIT_ASSERT_VALUES_EQUAL(response.operation().status(), Ydb::StatusIds::SUCCESS);
-    }
-
-    {
-        // Read should finish successfully and it doesn't see the write
-        auto response = AwaitResponse(runtime, simpleF);
-        UNIT_ASSERT_VALUES_EQUAL(response.operation().status(), Ydb::StatusIds::SUCCESS);
-        Ydb::Table::ExecuteQueryResult result;
-        response.operation().result().UnpackTo(&result);
-        UNIT_ASSERT_VALUES_EQUAL(
-            FormatResult(result),
-            "{ items { uint32_value: 3 } items { uint32_value: 2 } }, "
-            "{ items { uint32_value: 4 } items { uint32_value: 2 } }");
-    }
-
-    {
-        // Now we see the write
-        auto result = KqpSimpleExec(runtime, Q_(R"(
-        $rows = (
-            SELECT * FROM `/Root/table-1` WHERE key = 3 OR key = 5
-            UNION ALL
-            SELECT * FROM `/Root/table-2` WHERE key = 4 OR key = 6
-        );
-        SELECT key, value FROM $rows ORDER BY key)"));
-        TString expected = "{ items { uint32_value: 3 } items { uint32_value: 2 } }, "
-                           "{ items { uint32_value: 4 } items { uint32_value: 2 } }, "
-                           "{ items { uint32_value: 5 } items { uint32_value: 10 } }, "
-                           "{ items { uint32_value: 6 } items { uint32_value: 10 } }";
-        UNIT_ASSERT_VALUES_EQUAL(result, expected);
-    }
-}
-
 Y_UNIT_TEST_TWIN(TestOutOfOrderReadOnlyAllowed, StreamLookup) {
     TPortManager pm;
     NKikimrConfig::TAppConfig app;
@@ -1893,7 +1667,6 @@ Y_UNIT_TEST(MvccTestOutOfOrderRestartLocksSingleWithoutBarrier) {
     NKikimrConfig::TAppConfig app;
     app.MutableTableServiceConfig()->SetEnableKqpDataQueryStreamLookup(false);
     TServerSettings serverSettings(pm.GetPort(2134));
-    serverSettings.SetEnableMvccSnapshotReads(false);
     serverSettings.SetDomainName("Root")
         .SetAppConfig(app)
         .SetUseRealThreads(false);
@@ -2346,411 +2119,6 @@ Y_UNIT_TEST_TWIN(TestOutOfOrderNoBarrierRestartImmediateLongTail, StreamLookup)
     }
 }
 
-Y_UNIT_TEST(TestCopyTableNoDeadlock) {
-    TPortManager pm;
-    NKikimrConfig::TAppConfig app;
-    app.MutableTableServiceConfig()->SetEnableKqpDataQuerySourceRead(false);
-    TServerSettings serverSettings(pm.GetPort(2134));
-    serverSettings.SetEnableMvccSnapshotReads(false);
-    serverSettings.SetDomainName("Root")
-        .SetUseRealThreads(false)
-        .SetAppConfig(app);
-
-    Tests::TServer::TPtr server = new TServer(serverSettings);
-    auto &runtime = *server->GetRuntime();
-    auto sender = runtime.AllocateEdgeActor();
-
-    runtime.SetLogPriority(NKikimrServices::TX_DATASHARD, NLog::PRI_TRACE);
-    runtime.SetLogPriority(NKikimrServices::KQP_EXECUTER, NLog::PRI_DEBUG);
-
-    const bool usesVolatileTxs = runtime.GetAppData(0).FeatureFlags.GetEnableDataShardVolatileTransactions();
-
-    InitRoot(server, sender);
-
-    CreateShardedTable(server, sender, "/Root", "table-1", 1);
-    CreateShardedTable(server, sender, "/Root", "table-2", 1);
-
-    ExecSQL(server, sender, Q_("UPSERT INTO `/Root/table-1` (key, value) VALUES (1, 1);"));
-    ExecSQL(server, sender, Q_("UPSERT INTO `/Root/table-2` (key, value) VALUES (2, 1);"));
-
-    TString sessionId = CreateSessionRPC(runtime);
-    TString sessionRead = CreateSessionRPC(runtime);
-
-    TString txId;
-    {
-        auto result = KqpSimpleBegin(runtime, sessionId, txId, Q_(R"(
-            SELECT * FROM `/Root/table-1`
-            UNION ALL
-            SELECT * FROM `/Root/table-2`
-            ORDER BY key)"));
-        UNIT_ASSERT_VALUES_EQUAL(
-            result,
-            "{ items { uint32_value: 1 } items { uint32_value: 1 } }, "
-            "{ items { uint32_value: 2 } items { uint32_value: 1 } }");
-    }
-
-    // Capture and block all readset messages
-    TVector<THolder<IEventHandle>> readSets;
-    TVector<THolder<IEventHandle>> txProposes;
-    size_t seenPlanSteps = 0;
-    bool captureReadSets = true;
-    bool captureTxProposes = false;
-    auto captureRS = [&](TAutoPtr<IEventHandle> &event) -> auto {
-        switch (event->GetTypeRewrite()) {
-            case TEvTxProcessing::EvPlanStep:
-                Cerr << "---- observed EvPlanStep ----" << Endl;
-                ++seenPlanSteps;
-                break;
-            case TEvTxProcessing::EvReadSet:
-                Cerr << "---- observed EvReadSet ----" << Endl;
-                if (captureReadSets) {
-                    readSets.push_back(std::move(event));
-                    return TTestActorRuntime::EEventAction::DROP;
-                }
-                break;
-            case TEvTxProxy::EvProposeTransaction:
-                Cerr << "---- observed EvProposeTransaction ----" << Endl;
-                if (captureTxProposes) {
-                    txProposes.push_back(std::move(event));
-                    return TTestActorRuntime::EEventAction::DROP;
-                }
-                break;
-            default:
-                break;
-        }
-        return TTestActorRuntime::EEventAction::PROCESS;
-    };
-    auto prevObserverFunc = runtime.SetObserverFunc(captureRS);
-
-    // Send a commit request, it would block on readset exchange
-    auto fCommit = SendRequest(runtime, MakeSimpleRequestRPC(Q_(R"(
-        UPSERT INTO `/Root/table-1` (key, value) VALUES (3, 2);
-        UPSERT INTO `/Root/table-2` (key, value) VALUES (4, 2))"), sessionId, txId, true));
-
-    // Wait until we captured both readsets
-    const size_t expectedReadSets = usesVolatileTxs ? 4 : 2;
-    if (readSets.size() < expectedReadSets) {
-        TDispatchOptions options;
-        options.FinalEvents.emplace_back(
-            [&](IEventHandle &) -> bool {
-                return readSets.size() >= expectedReadSets;
-            });
-        runtime.DispatchEvents(options);
-    }
-    UNIT_ASSERT_VALUES_EQUAL(readSets.size(), expectedReadSets);
-
-    captureTxProposes = true;
-
-    // Now we send a distributed read, while stopping coordinator proposals
-    auto fRead = SendRequest(runtime, MakeSimpleRequestRPC(Q_(R"(
-        SELECT * FROM `/Root/table-1`
-        UNION ALL
-        SELECT * FROM `/Root/table-2`)"), sessionRead, "", true));
-
-    // Wait until we capture the propose request
-    if (txProposes.size() < 1) {
-        TDispatchOptions options;
-        options.FinalEvents.emplace_back(
-            [&](IEventHandle &) -> bool {
-                return txProposes.size() >= 1;
-            });
-        runtime.DispatchEvents(options);
-    }
-    UNIT_ASSERT_VALUES_EQUAL(txProposes.size(), 1u);
-
-    Cerr << "---- captured propose for data tx ----" << Endl;
-
-    // Now we send a copy table request, again blocking coordinator proposal
-    auto senderCopy = runtime.AllocateEdgeActor();
-    auto txIdCopy = AsyncCreateCopyTable(server, senderCopy, "/Root", "table-3", "/Root/table-2");
-
-    // Wait until we capture the propose request
-    if (txProposes.size() < 2) {
-        TDispatchOptions options;
-        options.FinalEvents.emplace_back(
-            [&](IEventHandle &) -> bool {
-                return txProposes.size() >= 2;
-            });
-        runtime.DispatchEvents(options);
-    }
-    UNIT_ASSERT_VALUES_EQUAL(txProposes.size(), 2u);
-
-    Cerr << "---- captured propose for copy tx ----" << Endl;
-
-    // Stop capturing stuff
-    captureReadSets = false;
-    captureTxProposes = false;
-
-    // Release copy tx propose and wait for plan steps (table-3, table-2 and schemeshard)
-    // It is important for copy tx to be planned *before* the read tx
-    seenPlanSteps = 0;
-    runtime.Send(txProposes[1].Release(), 0, /* via actor system */ true);
-    if (seenPlanSteps < 3) {
-        TDispatchOptions options;
-        options.FinalEvents.emplace_back(
-            [&](IEventHandle &) -> bool {
-                return seenPlanSteps >= 3;
-            });
-        runtime.DispatchEvents(options);
-    }
-    UNIT_ASSERT_VALUES_EQUAL(seenPlanSteps, 3u);
-
-    // Release read tx propose and wait for plan steps (table-1 and table-2)
-    // Now read tx will be planned *after* the copy tx
-    seenPlanSteps = 0;
-    runtime.Send(txProposes[0].Release(), 0, /* via actor system */ true);
-    if (seenPlanSteps < 2) {
-        TDispatchOptions options;
-        options.FinalEvents.emplace_back(
-            [&](IEventHandle &) -> bool {
-                return seenPlanSteps >= 2;
-            });
-        runtime.DispatchEvents(options);
-    }
-    UNIT_ASSERT_VALUES_EQUAL(seenPlanSteps, 2u);
-
-    // Sleep a little so that everything stops in a settled state
-    // Bug KIKIMR-7711 would cause copy tx and read tx to depend on each other
-    SimulateSleep(server, TDuration::Seconds(1));
-
-    // Release readsets, allowing the first commit to finish
-    for (auto& ev : readSets) {
-        runtime.Send(ev.Release(), 0, /* via actor system */ true);
-    }
-
-    // Wait for commit to complete, it must succeed
-    {
-        auto response = AwaitResponse(runtime, fCommit);
-        UNIT_ASSERT_VALUES_EQUAL(response.operation().status(), Ydb::StatusIds::SUCCESS);
-    }
-
-    // Wait for copy table tx to complete
-    WaitTxNotification(server, senderCopy, txIdCopy);
-
-    // Wait for distributed read to complete, it must succeed
-    {
-        auto response = AwaitResponse(runtime, fRead);
-        UNIT_ASSERT_VALUES_EQUAL(response.operation().status(), Ydb::StatusIds::SUCCESS);
-    }
-
-    // Verify copied table has data committed
-    UNIT_ASSERT_VALUES_EQUAL(
-        KqpSimpleExec(runtime, Q_(R"(
-            SELECT * FROM `/Root/table-3`
-            ORDER BY key)")),
-        "{ items { uint32_value: 2 } items { uint32_value: 1 } }, "
-        "{ items { uint32_value: 4 } items { uint32_value: 2 } }");
-}
-
-void VerifyNoActiveTransactions() {
-    using namespace NActors::NMemory::NPrivate;
-    const auto& instance = TMemoryTracker::Instance();
-    instance->Initialize();
-    std::vector<TMetric> metrics;
-    TMemoryTracker::Instance()->GatherMetrics(metrics);
-
-    for (size_t i : xrange(metrics.size())) {
-        if (instance->GetName(i) == TString(MemoryLabelActiveTransactionBody)) {
-            UNIT_ASSERT_VALUES_EQUAL(metrics[i].GetCount(), 0);
-            return;
-        }
-    }
-
-    UNIT_ASSERT_C(false, "Datashard/TActiveTransaction/TxBody metric not found");
-}
-
-Y_UNIT_TEST(TestPlannedCancelSplit) {
-    TPortManager pm;
-    NKikimrConfig::TAppConfig app;
-    app.MutableTableServiceConfig()->SetEnableKqpDataQuerySourceRead(false);
-    TServerSettings serverSettings(pm.GetPort(2134));
-    serverSettings.SetEnableMvccSnapshotReads(false);
-    serverSettings.SetDomainName("Root")
-        .SetUseRealThreads(false)
-        .SetAppConfig(app);
-
-    Tests::TServer::TPtr server = new TServer(serverSettings);
-    auto &runtime = *server->GetRuntime();
-    auto sender = runtime.AllocateEdgeActor();
-
-    runtime.SetLogPriority(NKikimrServices::TX_DATASHARD, NLog::PRI_TRACE);
-    runtime.SetLogPriority(NKikimrServices::KQP_EXECUTER, NLog::PRI_DEBUG);
-
-    InitRoot(server, sender);
-
-    CreateShardedTable(server, sender, "/Root", "table-1", 1);
-    CreateShardedTable(server, sender, "/Root", "table-2", 1);
-
-    ExecSQL(server, sender, Q_("UPSERT INTO `/Root/table-1` (key, value) VALUES (1, 1);"));
-    ExecSQL(server, sender, Q_("UPSERT INTO `/Root/table-2` (key, value) VALUES (2, 1);"));
-
-    TString senderRead2 = CreateSessionRPC(runtime);
-    TString senderRead1 = CreateSessionRPC(runtime);
-
-    auto shards1 = GetTableShards(server, sender, "/Root/table-1");
-    UNIT_ASSERT_VALUES_EQUAL(shards1.size(), 1u);
-    auto shards2 = GetTableShards(server, sender, "/Root/table-2");
-    UNIT_ASSERT_VALUES_EQUAL(shards2.size(), 1u);
-    TVector<ui64> tablets;
-    tablets.push_back(shards1[0]);
-    tablets.push_back(shards2[0]);
-
-    // Capture and block some messages
-    bool captureTxCancel = false;
-    bool captureTxPropose = false;
-    bool captureTxProposeResult = false;
-    TVector<THolder<IEventHandle>> txCancels;
-    TVector<THolder<IEventHandle>> txProposes;
-    TVector<THolder<IEventHandle>> txProposeResults;
-    auto captureMessages = [&](TAutoPtr<IEventHandle> &event) -> auto {
-        switch (event->GetTypeRewrite()) {
-            case TEvDataShard::EvProposeTransaction:
-                Cerr << "---- observed EvProposeTransaction ----" << Endl;
-                if (captureTxPropose) {
-                    txProposes.push_back(std::move(event));
-                    return TTestActorRuntime::EEventAction::DROP;
-                }
-                break;
-            case TEvDataShard::EvProposeTransactionResult:
-                Cerr << "---- observed EvProposeTransactionResult ----" << Endl;
-                if (captureTxProposeResult) {
-                    txProposeResults.push_back(std::move(event));
-                    return TTestActorRuntime::EEventAction::DROP;
-                }
-                break;
-            case TEvDataShard::EvCancelTransactionProposal:
-                Cerr << "---- observed EvCancelTransactionProposal ----" << Endl;
-                if (captureTxCancel) {
-                    txCancels.push_back(std::move(event));
-                    return TTestActorRuntime::EEventAction::DROP;
-                }
-                break;
-            default:
-                break;
-        }
-        return TTestActorRuntime::EEventAction::PROCESS;
-    };
-    auto prevObserverFunc = runtime.SetObserverFunc(captureMessages);
-
-    // Send a distributed read while capturing propose results
-    captureTxProposeResult = true;
-    auto fRead1 = SendRequest(runtime, MakeSimpleRequestRPC(Q_(R"(
-        SELECT * FROM `/Root/table-1`
-        UNION ALL
-        SELECT * FROM `/Root/table-2`)"), senderRead1, "", true));
-    if (txProposeResults.size() < 2) {
-        TDispatchOptions options;
-        options.FinalEvents.emplace_back(
-            [&](IEventHandle &) -> bool {
-                return txProposeResults.size() >= 2;
-            });
-        runtime.DispatchEvents(options);
-    }
-    UNIT_ASSERT_VALUES_EQUAL(txProposeResults.size(), 2u);
-    captureTxProposeResult = false;
-
-    // Remember which senders claim to be which shards
-    TVector<TActorId> actors(2);
-    for (auto& event : txProposeResults) {
-        TActorId actor = event->Sender;
-        const auto* msg = event->Get<TEvDataShard::TEvProposeTransactionResult>();
-        ui64 shard = msg->Record.GetOrigin();
-        for (size_t i = 0; i < tablets.size(); ++i) {
-            if (tablets[i] == shard) {
-                actors[i] = actor;
-            }
-        }
-        runtime.Send(event.Release(), 0, /* via actor system */ true);
-    }
-    txProposeResults.clear();
-
-    // Wait for the first query result, it must succeed
-    {
-        auto response = AwaitResponse(runtime, fRead1);
-        UNIT_ASSERT_VALUES_EQUAL(response.operation().status(), Ydb::StatusIds::SUCCESS);
-    }
-
-    // Send a distributed read again, while blocking propose messages
-    captureTxPropose = true;
-    auto fRead2 = SendRequest(runtime, MakeSimpleRequestRPC(Q_(R"(
-        SELECT * FROM `/Root/table-1`
-        UNION ALL
-        SELECT * FROM `/Root/table-2`)"), senderRead2, "", true));
-    if (txProposes.size() < 2) {
-        TDispatchOptions options;
-        options.FinalEvents.emplace_back(
-            [&](IEventHandle &) -> bool {
-                return txProposes.size() >= 2;
-            });
-        runtime.DispatchEvents(options);
-    }
-    UNIT_ASSERT_VALUES_EQUAL(txProposes.size(), 2u);
-    captureTxPropose = false;
-
-    // Simulate propose overloaded at the second table
-    captureTxCancel = true;
-    for (auto& event : txProposes) {
-        if (event && event->GetRecipientRewrite() == actors[1]) {
-            Cerr << "---- found propose for table-2 ----" << Endl;
-            const auto* msg = event->Get<TEvDataShard::TEvProposeTransaction>();
-            TActorId target = event->Sender;
-            auto* result = new TEvDataShard::TEvProposeTransactionResult(
-                msg->GetTxKind(),
-                tablets[1],
-                msg->GetTxId(),
-                NKikimrTxDataShard::TEvProposeTransactionResult::OVERLOADED);
-            Cerr << "Sending error result from " << actors[1] << " to " << target << Endl;
-            runtime.Send(new IEventHandle(target, actors[1], result), 0, /* via actor system */ true);
-            event.Reset(); // drop this propose event
-        }
-    }
-    if (txCancels.size() < 1) {
-        TDispatchOptions options;
-        options.FinalEvents.emplace_back(
-            [&](IEventHandle &) -> bool {
-                return txCancels.size() >= 1;
-            });
-        runtime.DispatchEvents(options);
-    }
-    UNIT_ASSERT_VALUES_EQUAL(txCancels.size(), 1u);
-    captureTxCancel = false;
-
-    // Now send propose and cancel messages in quick succession
-    for (auto& event : txProposes) {
-        if (event) {
-            runtime.Send(event.Release(), 0, /* via actor system */ true);
-        }
-    }
-    for (auto& event : txCancels) {
-        runtime.Send(event.Release(), 0, /* via actor system */ true);
-    }
-
-    // Wait for query to return an error
-    {
-        auto response = AwaitResponse(runtime, fRead2);
-        UNIT_ASSERT_VALUES_EQUAL(response.operation().status(), Ydb::StatusIds::OVERLOADED);
-    }
-
-    // Sleep a little so in case of a bug transaction is left in WaitForPlan state
-    SimulateSleep(server, TDuration::Seconds(1));
-
-    // Split would fail otherwise :(
-    SetSplitMergePartCountLimit(server->GetRuntime(), -1);
-
-    // Start split for table-1
-    TInstant splitStart = TInstant::Now();
-    auto senderSplit = runtime.AllocateEdgeActor();
-    ui64 txId = AsyncSplitTable(server, senderSplit, "/Root/table-1", tablets[0], 100);
-    WaitTxNotification(server, senderSplit, txId);
-
-    // Split shouldn't take too much time to complete
-    TDuration elapsed = TInstant::Now() - splitStart;
-    UNIT_ASSERT_C(elapsed < TDuration::Seconds(NValgrind::PlainOrUnderValgrind(2, 10)),
-        "Split needed " << elapsed.ToString() << " to complete, which is too long");
-
-    VerifyNoActiveTransactions();
-}
-
 Y_UNIT_TEST(TestPlannedTimeoutSplit) {
     TPortManager pm;
     TServerSettings serverSettings(pm.GetPort(2134));
@@ -4447,11 +3815,9 @@ Y_UNIT_TEST(TestSnapshotReadAfterStuckRW) {
     }
 }
 
-Y_UNIT_TEST_TWIN(TestSnapshotReadPriority, UnprotectedReads) {
+Y_UNIT_TEST(TestSnapshotReadPriority) {
     TPortManager pm;
     TServerSettings::TControls controls;
-    controls.MutableDataShardControls()->SetPrioritizedMvccSnapshotReads(1);
-    controls.MutableDataShardControls()->SetUnprotectedMvccSnapshotReads(UnprotectedReads ? 1 : 0);
     TServerSettings serverSettings(pm.GetPort(2134));
     serverSettings.SetDomainName("Root")
         .SetControls(controls)
@@ -4722,8 +4088,6 @@ Y_UNIT_TEST_TWIN(TestSnapshotReadPriority, UnprotectedReads) {
 Y_UNIT_TEST(TestUnprotectedReadsThenWriteVisibility) {
     TPortManager pm;
     TServerSettings::TControls controls;
-    controls.MutableDataShardControls()->SetPrioritizedMvccSnapshotReads(1);
-    controls.MutableDataShardControls()->SetUnprotectedMvccSnapshotReads(1);
     TServerSettings serverSettings(pm.GetPort(2134));
     serverSettings.SetDomainName("Root")
         .SetNodeCount(2)
@@ -5134,8 +4498,6 @@ Y_UNIT_TEST(UncommittedReadSetAck) {
 Y_UNIT_TEST(UncommittedReads) {
     TPortManager pm;
     TServerSettings::TControls controls;
-    controls.MutableDataShardControls()->SetPrioritizedMvccSnapshotReads(1);
-    controls.MutableDataShardControls()->SetUnprotectedMvccSnapshotReads(1);
 
     TServerSettings serverSettings(pm.GetPort(2134));
     serverSettings.SetDomainName("Root")
diff --git a/ydb/core/tx/datashard/datashard_ut_snapshot.cpp b/ydb/core/tx/datashard/datashard_ut_snapshot.cpp
index 19ba5a426868..f34a7e09942b 100644
--- a/ydb/core/tx/datashard/datashard_ut_snapshot.cpp
+++ b/ydb/core/tx/datashard/datashard_ut_snapshot.cpp
@@ -722,8 +722,6 @@ Y_UNIT_TEST_SUITE(DataShardSnapshots) {
     Y_UNIT_TEST(MvccSnapshotTailCleanup) {
         TPortManager pm;
         TServerSettings::TControls controls;
-        controls.MutableDataShardControls()->SetPrioritizedMvccSnapshotReads(1);
-        controls.MutableDataShardControls()->SetUnprotectedMvccSnapshotReads(1);
         TServerSettings serverSettings(pm.GetPort(2134));
         serverSettings.SetDomainName("Root")
             .SetUseRealThreads(false)
@@ -806,8 +804,6 @@ Y_UNIT_TEST_SUITE(DataShardSnapshots) {
     Y_UNIT_TEST(MvccSnapshotAndSplit) {
         TPortManager pm;
         TServerSettings::TControls controls;
-        controls.MutableDataShardControls()->SetPrioritizedMvccSnapshotReads(1);
-        controls.MutableDataShardControls()->SetUnprotectedMvccSnapshotReads(1);
         TServerSettings serverSettings(pm.GetPort(2134));
         serverSettings.SetDomainName("Root")
             .SetUseRealThreads(false)
@@ -971,8 +967,6 @@ Y_UNIT_TEST_SUITE(DataShardSnapshots) {
     Y_UNIT_TEST(MvccSnapshotReadWithLongPlanQueue) {
         TPortManager pm;
         TServerSettings::TControls controls;
-        controls.MutableDataShardControls()->SetPrioritizedMvccSnapshotReads(1);
-        controls.MutableDataShardControls()->SetUnprotectedMvccSnapshotReads(1);
 
         TServerSettings serverSettings(pm.GetPort(2134));
         serverSettings.SetDomainName("Root")
@@ -1349,8 +1343,6 @@ Y_UNIT_TEST_SUITE(DataShardSnapshots) {
     Y_UNIT_TEST(MvccSnapshotLockedWrites) {
         TPortManager pm;
         TServerSettings::TControls controls;
-        controls.MutableDataShardControls()->SetPrioritizedMvccSnapshotReads(1);
-        controls.MutableDataShardControls()->SetUnprotectedMvccSnapshotReads(1);
         controls.MutableDataShardControls()->SetEnableLockedWrites(1);
 
         TServerSettings serverSettings(pm.GetPort(2134));
@@ -1443,8 +1435,6 @@ Y_UNIT_TEST_SUITE(DataShardSnapshots) {
     Y_UNIT_TEST(MvccSnapshotLockedWritesRestart) {
         TPortManager pm;
         TServerSettings::TControls controls;
-        controls.MutableDataShardControls()->SetPrioritizedMvccSnapshotReads(1);
-        controls.MutableDataShardControls()->SetUnprotectedMvccSnapshotReads(1);
         controls.MutableDataShardControls()->SetEnableLockedWrites(1);
 
         TServerSettings serverSettings(pm.GetPort(2134));
@@ -1544,8 +1534,6 @@ Y_UNIT_TEST_SUITE(DataShardSnapshots) {
     Y_UNIT_TEST(MvccSnapshotLockedWritesWithoutConflicts) {
         TPortManager pm;
         TServerSettings::TControls controls;
-        controls.MutableDataShardControls()->SetPrioritizedMvccSnapshotReads(1);
-        controls.MutableDataShardControls()->SetUnprotectedMvccSnapshotReads(1);
         controls.MutableDataShardControls()->SetEnableLockedWrites(1);
 
         TServerSettings serverSettings(pm.GetPort(2134));
@@ -1673,8 +1661,6 @@ Y_UNIT_TEST_SUITE(DataShardSnapshots) {
     Y_UNIT_TEST(MvccSnapshotLockedWritesWithConflicts) {
         TPortManager pm;
         TServerSettings::TControls controls;
-        controls.MutableDataShardControls()->SetPrioritizedMvccSnapshotReads(1);
-        controls.MutableDataShardControls()->SetUnprotectedMvccSnapshotReads(1);
         controls.MutableDataShardControls()->SetEnableLockedWrites(1);
 
         TServerSettings serverSettings(pm.GetPort(2134));
@@ -1839,8 +1825,6 @@ Y_UNIT_TEST_SUITE(DataShardSnapshots) {
     Y_UNIT_TEST(MvccSnapshotReadLockedWrites) {
         TPortManager pm;
         TServerSettings::TControls controls;
-        controls.MutableDataShardControls()->SetPrioritizedMvccSnapshotReads(1);
-        controls.MutableDataShardControls()->SetUnprotectedMvccSnapshotReads(1);
         controls.MutableDataShardControls()->SetEnableLockedWrites(1);
 
         TServerSettings serverSettings(pm.GetPort(2134));
@@ -1997,8 +1981,6 @@ Y_UNIT_TEST_SUITE(DataShardSnapshots) {
     Y_UNIT_TEST(MvccSnapshotLockedWritesWithReadConflicts) {
         TPortManager pm;
         TServerSettings::TControls controls;
-        controls.MutableDataShardControls()->SetPrioritizedMvccSnapshotReads(1);
-        controls.MutableDataShardControls()->SetUnprotectedMvccSnapshotReads(1);
         controls.MutableDataShardControls()->SetEnableLockedWrites(1);
 
         NKikimrConfig::TAppConfig app;
@@ -2146,8 +2128,6 @@ Y_UNIT_TEST_SUITE(DataShardSnapshots) {
     Y_UNIT_TEST(LockedWriteBulkUpsertConflict) {
         TPortManager pm;
         TServerSettings::TControls controls;
-        controls.MutableDataShardControls()->SetPrioritizedMvccSnapshotReads(1);
-        controls.MutableDataShardControls()->SetUnprotectedMvccSnapshotReads(1);
         controls.MutableDataShardControls()->SetEnableLockedWrites(1);
 
         TServerSettings serverSettings(pm.GetPort(2134));
@@ -2244,8 +2224,6 @@ Y_UNIT_TEST_SUITE(DataShardSnapshots) {
     Y_UNIT_TEST(LockedWriteReuseAfterCommit) {
         TPortManager pm;
         TServerSettings::TControls controls;
-        controls.MutableDataShardControls()->SetPrioritizedMvccSnapshotReads(1);
-        controls.MutableDataShardControls()->SetUnprotectedMvccSnapshotReads(1);
         controls.MutableDataShardControls()->SetEnableLockedWrites(1);
 
         TServerSettings serverSettings(pm.GetPort(2134));
@@ -2329,8 +2307,6 @@ Y_UNIT_TEST_SUITE(DataShardSnapshots) {
     Y_UNIT_TEST(LockedWriteDistributedCommitSuccess) {
         TPortManager pm;
         TServerSettings::TControls controls;
-        controls.MutableDataShardControls()->SetPrioritizedMvccSnapshotReads(1);
-        controls.MutableDataShardControls()->SetUnprotectedMvccSnapshotReads(1);
         controls.MutableDataShardControls()->SetEnableLockedWrites(1);
 
         TServerSettings serverSettings(pm.GetPort(2134));
@@ -2436,8 +2412,6 @@ Y_UNIT_TEST_SUITE(DataShardSnapshots) {
     Y_UNIT_TEST(LockedWriteDistributedCommitAborted) {
         TPortManager pm;
         TServerSettings::TControls controls;
-        controls.MutableDataShardControls()->SetPrioritizedMvccSnapshotReads(1);
-        controls.MutableDataShardControls()->SetUnprotectedMvccSnapshotReads(1);
         controls.MutableDataShardControls()->SetEnableLockedWrites(1);
 
         TServerSettings serverSettings(pm.GetPort(2134));
@@ -2548,8 +2522,6 @@ Y_UNIT_TEST_SUITE(DataShardSnapshots) {
     Y_UNIT_TEST(LockedWriteDistributedCommitFreeze) {
         TPortManager pm;
         TServerSettings::TControls controls;
-        controls.MutableDataShardControls()->SetPrioritizedMvccSnapshotReads(1);
-        controls.MutableDataShardControls()->SetUnprotectedMvccSnapshotReads(1);
         controls.MutableDataShardControls()->SetEnableLockedWrites(1);
 
         TServerSettings serverSettings(pm.GetPort(2134));
@@ -2675,8 +2647,6 @@ Y_UNIT_TEST_SUITE(DataShardSnapshots) {
     Y_UNIT_TEST(LockedWriteDistributedCommitCrossConflict) {
         TPortManager pm;
         TServerSettings::TControls controls;
-        controls.MutableDataShardControls()->SetPrioritizedMvccSnapshotReads(1);
-        controls.MutableDataShardControls()->SetUnprotectedMvccSnapshotReads(1);
         controls.MutableDataShardControls()->SetEnableLockedWrites(1);
 
         TServerSettings serverSettings(pm.GetPort(2134));
@@ -2857,8 +2827,6 @@ Y_UNIT_TEST_SUITE(DataShardSnapshots) {
     Y_UNIT_TEST(LockedWriteCleanupOnSplit) {
         TPortManager pm;
         TServerSettings::TControls controls;
-        controls.MutableDataShardControls()->SetPrioritizedMvccSnapshotReads(1);
-        controls.MutableDataShardControls()->SetUnprotectedMvccSnapshotReads(1);
         controls.MutableDataShardControls()->SetEnableLockedWrites(1);
 
         TServerSettings serverSettings(pm.GetPort(2134));
@@ -2954,8 +2922,6 @@ Y_UNIT_TEST_SUITE(DataShardSnapshots) {
     Y_UNIT_TEST(LockedWriteCleanupOnCopyTable) {
         TPortManager pm;
         TServerSettings::TControls controls;
-        controls.MutableDataShardControls()->SetPrioritizedMvccSnapshotReads(1);
-        controls.MutableDataShardControls()->SetUnprotectedMvccSnapshotReads(1);
         controls.MutableDataShardControls()->SetEnableLockedWrites(1);
 
         TServerSettings serverSettings(pm.GetPort(2134));
@@ -3076,8 +3042,6 @@ Y_UNIT_TEST_SUITE(DataShardSnapshots) {
     Y_UNIT_TEST_TWIN(LockedWriteWithAsyncIndex, WithRestart) {
         TPortManager pm;
         TServerSettings::TControls controls;
-        controls.MutableDataShardControls()->SetPrioritizedMvccSnapshotReads(1);
-        controls.MutableDataShardControls()->SetUnprotectedMvccSnapshotReads(1);
         controls.MutableDataShardControls()->SetEnableLockedWrites(1);
 
         TServerSettings serverSettings(pm.GetPort(2134));
@@ -3211,8 +3175,6 @@ Y_UNIT_TEST_SUITE(DataShardSnapshots) {
     Y_UNIT_TEST(LockedWritesLimitedPerKey) {
         TPortManager pm;
         TServerSettings::TControls controls;
-        controls.MutableDataShardControls()->SetPrioritizedMvccSnapshotReads(1);
-        controls.MutableDataShardControls()->SetUnprotectedMvccSnapshotReads(1);
         controls.MutableDataShardControls()->SetEnableLockedWrites(1);
         controls.MutableDataShardControls()->SetMaxLockedWritesPerKey(2);
 
@@ -3407,8 +3369,6 @@ Y_UNIT_TEST_SUITE(DataShardSnapshots) {
     Y_UNIT_TEST(LockedWriteWithAsyncIndexAndVolatileCommit) {
         TPortManager pm;
         TServerSettings::TControls controls;
-        controls.MutableDataShardControls()->SetPrioritizedMvccSnapshotReads(1);
-        controls.MutableDataShardControls()->SetUnprotectedMvccSnapshotReads(1);
         controls.MutableDataShardControls()->SetEnableLockedWrites(1);
 
         TServerSettings serverSettings(pm.GetPort(2134));
diff --git a/ydb/core/tx/datashard/ut_common/datashard_ut_common.h b/ydb/core/tx/datashard/ut_common/datashard_ut_common.h
index 752631f4e7e8..6b2482cd90c3 100644
--- a/ydb/core/tx/datashard/ut_common/datashard_ut_common.h
+++ b/ydb/core/tx/datashard/ut_common/datashard_ut_common.h
@@ -56,7 +56,6 @@ class TTester : public TNonCopyable {
         bool DelayReadSet;
         bool DelayData;
         bool RebootOnDelay;
-        std::optional<bool> Mvcc;
         ui64 ExecutorCacheSize;
 
         TOptions(ui64 firstStep = 0)
@@ -71,7 +70,6 @@ class TTester : public TNonCopyable {
 
         void EnableOutOfOrder(ui32 num = 8) { NumActiveTx = num; }
         void EnableSoftUpdates() { SoftUpdates = true; }
-        void EnableMvcc(std::optional<bool> enabled = {true}) { Mvcc = enabled; }
 
         TString PartConfig() const {
             TString pipelineConfig = Sprintf(R"(PipelineConfig {
diff --git a/ydb/core/tx/tx_proxy/datareq.cpp b/ydb/core/tx/tx_proxy/datareq.cpp
index 88e7744cb4e2..d5c66d3f6ab4 100644
--- a/ydb/core/tx/tx_proxy/datareq.cpp
+++ b/ydb/core/tx/tx_proxy/datareq.cpp
@@ -993,7 +993,6 @@ void TDataReq::ProcessFlatMKQLResolve(NSchemeCache::TSchemeCacheRequest *cacheRe
             rsCount == 0 &&
             engine.GetAffectedShardCount() > 1 &&
             ((TxFlags & NTxDataShard::TTxFlags::ForceOnline) == 0) &&
-            AppData(ctx)->FeatureFlags.GetEnableMvccSnapshotReads() &&
             !DatabaseName.empty());
 
     if (forceSnapshot) {
diff --git a/ydb/tests/functional/serverless/test_serverless.py b/ydb/tests/functional/serverless/test_serverless.py
index 2659b5db7a62..99d795fe989a 100644
--- a/ydb/tests/functional/serverless/test_serverless.py
+++ b/ydb/tests/functional/serverless/test_serverless.py
@@ -23,7 +23,6 @@
     erasure=Erasure.NONE,
     nodes=1,
     enable_metering=True,
-    disable_mvcc=True,
     additional_log_configs={
         'TX_PROXY': LogLevels.DEBUG,
         'KQP_PROXY': LogLevels.DEBUG,
@@ -48,7 +47,10 @@
     },
     enforce_user_token_requirement=True,
     default_user_sid='user@builtin',
-    extra_feature_flags=['enable_serverless_exclusive_dynamic_nodes']
+    extra_feature_flags=['enable_serverless_exclusive_dynamic_nodes'],
+    datashard_config={
+        'keep_snapshot_timeout': 5000,
+    },
 )
 
 
diff --git a/ydb/tests/library/harness/kikimr_config.py b/ydb/tests/library/harness/kikimr_config.py
index 41b409d66bb6..5a8c3a680758 100644
--- a/ydb/tests/library/harness/kikimr_config.py
+++ b/ydb/tests/library/harness/kikimr_config.py
@@ -143,7 +143,6 @@ def __init__(
             public_http_config=None,
             enable_datastreams=False,
             auth_config_path=None,
-            disable_mvcc=False,
             enable_public_api_external_blobs=False,
             node_kind=None,
             bs_cache_file_path=None,
@@ -158,6 +157,7 @@ def __init__(
             extra_feature_flags=None,  # list[str]
             extra_grpc_services=None,  # list[str]
             hive_config=None,
+            datashard_config=None,
             enforce_user_token_requirement=False,
             default_user_sid=None
     ):
@@ -260,7 +260,6 @@ def __init__(
             self.yaml_config["table_service_config"]["enable_kqp_data_query_stream_lookup"] = False
 
         self.yaml_config["feature_flags"]["enable_public_api_external_blobs"] = enable_public_api_external_blobs
-        self.yaml_config["feature_flags"]["enable_mvcc"] = "VALUE_FALSE" if disable_mvcc else "VALUE_TRUE"
         for extra_feature_flag in extra_feature_flags:
             self.yaml_config["feature_flags"][extra_feature_flag] = True
         if enable_alter_database_create_hive_first:
@@ -344,6 +343,9 @@ def __init__(
         if hive_config:
             self.yaml_config["hive_config"] = hive_config
 
+        if datashard_config:
+            self.yaml_config["data_shard_config"] = datashard_config
+
         self.__build()
 
         if self.grpc_ssl_enable: