diff --git a/ydb/core/protos/tx_datashard.proto b/ydb/core/protos/tx_datashard.proto
index 599ffff4482c..6a1313776694 100644
--- a/ydb/core/protos/tx_datashard.proto
+++ b/ydb/core/protos/tx_datashard.proto
@@ -830,6 +830,7 @@ message TEvUploadRowsRequest {
     optional bool WriteToTableShadow = 5;
     optional uint64 OverloadSubscribe = 7;
     optional bool UpsertIfExists = 8 [ default = false ];
+    optional uint64 SchemaVersion = 9;
 }
 
 message TEvUploadRowsResponse {
diff --git a/ydb/core/tx/datashard/datashard_common_upload.cpp b/ydb/core/tx/datashard/datashard_common_upload.cpp
index 5f1161d04f40..46c8977a6335 100644
--- a/ydb/core/tx/datashard/datashard_common_upload.cpp
+++ b/ydb/core/tx/datashard/datashard_common_upload.cpp
@@ -47,6 +47,17 @@ bool TCommonUploadOps<TEvRequest, TEvResponse>::Execute(TDataShard* self, TTrans
         return true;
     }
 
+    if (record.GetSchemaVersion() && tableInfo.GetTableSchemaVersion() &&
+        record.GetSchemaVersion() != tableInfo.GetTableSchemaVersion())
+    {
+        SetError(NKikimrTxDataShard::TError::SCHEME_ERROR, TStringBuilder()
+            << "Schema version mismatch"
+            << ": requested " << record.GetSchemaVersion()
+            << ", expected " << tableInfo.GetTableSchemaVersion()
+            << ". Retry request with an updated schema.");
+        return true;
+    }
+
     for (size_t i = 0; i < tableInfo.KeyColumnIds.size(); ++i) {
         if (record.GetRowScheme().GetKeyColumnIds(i) != tableInfo.KeyColumnIds[i]) {
             SetError(NKikimrTxDataShard::TError::SCHEME_ERROR, Sprintf("Key column schema at position %" PRISZT, i));
diff --git a/ydb/core/tx/datashard/datashard_ut_upload_rows.cpp b/ydb/core/tx/datashard/datashard_ut_upload_rows.cpp
index 9b71c4c781a7..0c82d8648601 100644
--- a/ydb/core/tx/datashard/datashard_ut_upload_rows.cpp
+++ b/ydb/core/tx/datashard/datashard_ut_upload_rows.cpp
@@ -849,6 +849,94 @@ Y_UNIT_TEST_SUITE(TTxDataShardUploadRows) {
     Y_UNIT_TEST(ShouldRejectOnChangeQueueOverflowAndRetry) {
         DoShouldRejectOnChangeQueueOverflow(true);
     }
+
+    Y_UNIT_TEST(BulkUpsertDuringAddIndexRaceCorruption) {
+        TPortManager pm;
+        TServerSettings serverSettings(pm.GetPort(2134));
+        serverSettings.SetDomainName("Root")
+            .SetUseRealThreads(false)
+            .SetDomainPlanResolution(1000);
+
+        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::TX_PROXY, NLog::PRI_DEBUG);
+
+        InitRoot(server, sender);
+
+        auto opts = TShardedTableOptions()
+                        .Shards(1)
+                        .Columns({
+                            {"key", "Uint32", true, false},
+                            {"value", "Uint32", false, false}});
+        CreateShardedTable(server, sender, "/Root", "table-1", opts);
+
+        ExecSQL(server, sender, "UPSERT INTO `/Root/table-1` (key, value) VALUES (1, 2), (3, 4);");
+
+        std::vector<std::unique_ptr<IEventHandle>> bulkUpserts;
+        auto captureBulkUpserts = runtime.AddObserver<TEvDataShard::TEvUploadRowsRequest>(
+            [&](TEvDataShard::TEvUploadRowsRequest::TPtr& ev) {
+                bulkUpserts.emplace_back(ev.Release());
+            });
+
+        // Start writing to key 5 using bulk upsert
+        NThreading::TFuture<Ydb::Table::BulkUpsertResponse> bulkUpsertFuture;
+        {
+            Ydb::Table::BulkUpsertRequest request;
+            request.set_table("/Root/table-1");
+            auto* r = request.mutable_rows();
+
+            auto* reqRowType = r->mutable_type()->mutable_list_type()->mutable_item()->mutable_struct_type();
+            auto* reqKeyType = reqRowType->add_members();
+            reqKeyType->set_name("key");
+            reqKeyType->mutable_type()->set_type_id(Ydb::Type::UINT32);
+            auto* reqValueType = reqRowType->add_members();
+            reqValueType->set_name("value");
+            reqValueType->mutable_type()->set_type_id(Ydb::Type::UINT32);
+
+            auto* reqRows = r->mutable_value();
+            auto* row1 = reqRows->add_items();
+            row1->add_items()->set_uint32_value(5);
+            row1->add_items()->set_uint32_value(6);
+
+            using TEvBulkUpsertRequest = NKikimr::NGRpcService::TGrpcRequestOperationCall<
+                Ydb::Table::BulkUpsertRequest, Ydb::Table::BulkUpsertResponse>;
+            bulkUpsertFuture = NRpcService::DoLocalRpc<TEvBulkUpsertRequest>(
+                std::move(request), "/Root", "", runtime.GetActorSystem(0));
+        }
+
+        WaitFor(runtime, [&]{ return bulkUpserts.size() > 0; }, "captured bulk upsert");
+        UNIT_ASSERT_VALUES_EQUAL(bulkUpserts.size(), 1u);
+        captureBulkUpserts.Remove();
+
+        Cerr << "... creating a by_value index" << Endl;
+        WaitTxNotification(server, sender,
+            AsyncAlterAddIndex(server, "/Root", "/Root/table-1",
+                TShardedTableOptions::TIndex{"by_value", {"value"}, {}, NKikimrSchemeOp::EIndexTypeGlobal}));
+        runtime.SimulateSleep(TDuration::Seconds(1));
+
+        // Unblock the captured bulk upsert
+        for (auto& ev : bulkUpserts) {
+            runtime.Send(ev.release(), 0, true);
+        }
+        bulkUpserts.clear();
+
+        // Wait for the bulk upsert to finish
+        Cerr << "... waiting for bulk upsert to finish" << Endl;
+        auto response = AwaitResponse(runtime, std::move(bulkUpsertFuture));
+        Cerr << "... bulk upsert finished with status " << response.operation().status() << Endl;
+
+        // Whether bulk upsert succeeds or not we shouldn't get a corrupted index (bug KIKIMR-20765)
+        auto data1 = KqpSimpleExec(runtime, Q_(R"(
+            SELECT key, value FROM `/Root/table-1` ORDER BY key
+        )"));
+        auto data2 = KqpSimpleExec(runtime, Q_(R"(
+            SELECT key, value FROM `/Root/table-1` VIEW by_value ORDER BY key
+        )"));
+        UNIT_ASSERT_VALUES_EQUAL(data1, data2);
+    }
 }
 
 } // namespace NKikimr
diff --git a/ydb/core/tx/tx_proxy/upload_rows_common_impl.h b/ydb/core/tx/tx_proxy/upload_rows_common_impl.h
index 907578f0346d..0765fe1a29fc 100644
--- a/ydb/core/tx/tx_proxy/upload_rows_common_impl.h
+++ b/ydb/core/tx/tx_proxy/upload_rows_common_impl.h
@@ -1039,6 +1039,9 @@ class TUploadRowsBase : public TActorBootstrapped<TUploadRowsBase<DerivedActivit
                 ev->Record.SetCancelDeadlineMs(Deadline().MilliSeconds());
 
                 ev->Record.SetTableId(keyRange->TableId.PathId.LocalPathId);
+                if (keyRange->TableId.SchemaVersion) {
+                    ev->Record.SetSchemaVersion(keyRange->TableId.SchemaVersion);
+                }
                 for (const auto& fd : KeyColumnPositions) {
                     ev->Record.MutableRowScheme()->AddKeyColumnIds(fd.ColId);
                 }