diff --git a/ydb/core/kafka_proxy/actors/kafka_api_versions_actor.cpp b/ydb/core/kafka_proxy/actors/kafka_api_versions_actor.cpp
index 96c628477a5c..dc74d519630a 100644
--- a/ydb/core/kafka_proxy/actors/kafka_api_versions_actor.cpp
+++ b/ydb/core/kafka_proxy/actors/kafka_api_versions_actor.cpp
@@ -30,21 +30,21 @@ TApiVersionsResponseData::TPtr GetApiVersions() {
     TApiVersionsResponseData::TPtr response = std::make_shared<TApiVersionsResponseData>();
     response->ErrorCode = EKafkaErrors::NONE_ERROR;
 
-    AddApiKey<TProduceRequestData>(response->ApiKeys, PRODUCE, {.MinVersion=3});
-    AddApiKey<TApiVersionsRequestData>(response->ApiKeys, API_VERSIONS);
-    AddApiKey<TMetadataRequestData>(response->ApiKeys, METADATA);
-    AddApiKey<TInitProducerIdRequestData>(response->ApiKeys, INIT_PRODUCER_ID);
-    AddApiKey<TSaslHandshakeRequestData>(response->ApiKeys, SASL_HANDSHAKE);
-    AddApiKey<TSaslAuthenticateRequestData>(response->ApiKeys, SASL_AUTHENTICATE);
-    AddApiKey<TListOffsetsRequestData>(response->ApiKeys, LIST_OFFSETS);
+    AddApiKey<TProduceRequestData>(response->ApiKeys, PRODUCE, {.MinVersion=3, .MaxVersion=9});
+    AddApiKey<TApiVersionsRequestData>(response->ApiKeys, API_VERSIONS, {.MaxVersion=2});
+    AddApiKey<TMetadataRequestData>(response->ApiKeys, METADATA, {.MaxVersion=9});
+    AddApiKey<TInitProducerIdRequestData>(response->ApiKeys, INIT_PRODUCER_ID, {.MaxVersion=4});
+    AddApiKey<TSaslHandshakeRequestData>(response->ApiKeys, SASL_HANDSHAKE, {.MaxVersion=1});
+    AddApiKey<TSaslAuthenticateRequestData>(response->ApiKeys, SASL_AUTHENTICATE, {.MaxVersion=2});
+    AddApiKey<TListOffsetsRequestData>(response->ApiKeys, LIST_OFFSETS, {.MinVersion=1, .MaxVersion=1});
     AddApiKey<TFetchRequestData>(response->ApiKeys, FETCH, {.MaxVersion=3});
-    AddApiKey<TJoinGroupRequestData>(response->ApiKeys, JOIN_GROUP);
-    AddApiKey<TSyncGroupRequestData>(response->ApiKeys, SYNC_GROUP);
-    AddApiKey<TLeaveGroupRequestData>(response->ApiKeys, LEAVE_GROUP);
-    AddApiKey<THeartbeatRequestData>(response->ApiKeys, HEARTBEAT);
-    AddApiKey<TFindCoordinatorRequestData>(response->ApiKeys, FIND_COORDINATOR);
-    AddApiKey<TOffsetCommitRequestData>(response->ApiKeys, OFFSET_COMMIT, {.MaxVersion=1});
-    AddApiKey<TOffsetFetchRequestData>(response->ApiKeys, OFFSET_FETCH);
+    AddApiKey<TJoinGroupRequestData>(response->ApiKeys, JOIN_GROUP, {.MaxVersion=9});
+    AddApiKey<TSyncGroupRequestData>(response->ApiKeys, SYNC_GROUP, {.MaxVersion=3});
+    AddApiKey<TLeaveGroupRequestData>(response->ApiKeys, LEAVE_GROUP, {.MaxVersion=5});
+    AddApiKey<THeartbeatRequestData>(response->ApiKeys, HEARTBEAT, {.MaxVersion=4});
+    AddApiKey<TFindCoordinatorRequestData>(response->ApiKeys, FIND_COORDINATOR, {.MaxVersion=0});
+    AddApiKey<TOffsetCommitRequestData>(response->ApiKeys, OFFSET_COMMIT, {.MaxVersion=0});
+    AddApiKey<TOffsetFetchRequestData>(response->ApiKeys, OFFSET_FETCH, {.MaxVersion=8});
 
     return response;
 }
diff --git a/ydb/core/kafka_proxy/actors/kafka_find_coordinator_actor.cpp b/ydb/core/kafka_proxy/actors/kafka_find_coordinator_actor.cpp
index 63709d8385c4..c1f473f59f92 100644
--- a/ydb/core/kafka_proxy/actors/kafka_find_coordinator_actor.cpp
+++ b/ydb/core/kafka_proxy/actors/kafka_find_coordinator_actor.cpp
@@ -49,6 +49,11 @@ void TKafkaFindCoordinatorActor::SendResponseOkAndDie(const TString& host, i32 p
         response->Coordinators.push_back(coordinator);
     }
 
+    response->ErrorCode = NONE_ERROR;
+    response->Host = host;
+    response->Port = port;
+    response->NodeId = nodeId;
+
     Send(Context->ConnectionId, new TEvKafka::TEvResponse(CorrelationId, response, static_cast<EKafkaErrors>(response->ErrorCode)));
     Die(ctx);
 }
diff --git a/ydb/core/kafka_proxy/actors/kafka_offset_fetch_actor.cpp b/ydb/core/kafka_proxy/actors/kafka_offset_fetch_actor.cpp
index 01cee28a259c..96893aaa59ce 100644
--- a/ydb/core/kafka_proxy/actors/kafka_offset_fetch_actor.cpp
+++ b/ydb/core/kafka_proxy/actors/kafka_offset_fetch_actor.cpp
@@ -204,6 +204,7 @@ TOffsetFetchResponseData::TPtr TKafkaOffsetFetchActor::GetOffsetFetchResponse()
                 partition.CommittedOffset = sourcePartition.CommittedOffset;
                 partition.PartitionIndex = sourcePartition.PartitionIndex;
                 partition.ErrorCode = sourcePartition.ErrorCode;
+                topic.Partitions.push_back(partition);
             }
             response->Topics.push_back(topic);
         }
diff --git a/ydb/core/kafka_proxy/actors/kafka_read_session_actor.cpp b/ydb/core/kafka_proxy/actors/kafka_read_session_actor.cpp
index e788f7ceb736..e8f0a2024501 100644
--- a/ydb/core/kafka_proxy/actors/kafka_read_session_actor.cpp
+++ b/ydb/core/kafka_proxy/actors/kafka_read_session_actor.cpp
@@ -86,8 +86,8 @@ void TKafkaReadSessionActor::HandleJoinGroup(TEvKafka::TEvJoinGroupRequest::TPtr
 
     switch (ReadStep) {
         case WAIT_JOIN_GROUP: { // join first time
-            if (joinGroupRequest->ProtocolType != SUPPORTED_JOIN_GROUP_PROTOCOL) {
-                SendJoinGroupResponseFail(ctx, ev->Get()->CorrelationId, INVALID_REQUEST, TStringBuilder() << "unknown protocolType# " << joinGroupRequest->ProtocolType);
+            if (joinGroupRequest->ProtocolType.has_value() && !joinGroupRequest->ProtocolType.value().empty() && joinGroupRequest->ProtocolType.value() != SUPPORTED_JOIN_GROUP_PROTOCOL) {
+                SendJoinGroupResponseFail(ctx, ev->Get()->CorrelationId, INVALID_REQUEST, TStringBuilder() << "unknown protocolType# " << joinGroupRequest->ProtocolType.value());
                 CloseReadSession(ctx);
                 return;  
             }
@@ -156,8 +156,8 @@ void TKafkaReadSessionActor::HandleSyncGroup(TEvKafka::TEvSyncGroupRequest::TPtr
         return;
     }
 
-    if (syncGroupRequest->ProtocolType != SUPPORTED_JOIN_GROUP_PROTOCOL) {
-        SendJoinGroupResponseFail(ctx, ev->Get()->CorrelationId, INVALID_REQUEST, TStringBuilder() << "unknown protocolType# " << syncGroupRequest->ProtocolType);
+    if (syncGroupRequest->ProtocolType.has_value() && !syncGroupRequest->ProtocolType.value().empty() && syncGroupRequest->ProtocolType.value() != SUPPORTED_JOIN_GROUP_PROTOCOL) {
+        SendSyncGroupResponseFail(ctx, ev->Get()->CorrelationId, INVALID_REQUEST, TStringBuilder() << "unknown protocolType# " << syncGroupRequest->ProtocolType.value());
         CloseReadSession(ctx);
         return;  
     }
@@ -361,9 +361,9 @@ TConsumerProtocolAssignment TKafkaReadSessionActor::BuildAssignmentAndInformBala
         for (auto part: finalPartitionsToRead) {
             KAFKA_LOG_D("SYNC_GROUP assigned partition number: " << part);
             topicPartition.Partitions.push_back(part);
-            assignment.AssignedPartitions.push_back(topicPartition);
             partitions.ReadingNow.emplace(part);
         }
+        assignment.AssignedPartitions.push_back(topicPartition);
     }
 
     return assignment;
diff --git a/ydb/core/kafka_proxy/kafka_consumer_protocol.cpp b/ydb/core/kafka_proxy/kafka_consumer_protocol.cpp
index dd2e52eb7a64..ce54125ffd56 100644
--- a/ydb/core/kafka_proxy/kafka_consumer_protocol.cpp
+++ b/ydb/core/kafka_proxy/kafka_consumer_protocol.cpp
@@ -143,12 +143,20 @@ void TConsumerProtocolAssignment::Read(TKafkaReadable& _readable, TKafkaVersion
 }
 
 void TConsumerProtocolAssignment::Write(TKafkaWritable& _writable, TKafkaVersion _version) const {
+    auto useVarintSize = _version > 3;
     _version = ASSIGNMENT_VERSION;
+
     if (!NPrivate::VersionCheck<MessageMeta::PresentVersions.Min, MessageMeta::PresentVersions.Max>(_version)) {
         ythrow yexception() << "Can't write version " << _version << " of TConsumerProtocolAssignment";
     }
     
-    _writable.writeUnsignedVarint(Size(ASSIGNMENT_VERSION) + 1);
+    if (useVarintSize) {
+        _writable.writeUnsignedVarint(Size(_version) + 1);
+    } else {
+        TKafkaInt32 size = Size(_version);
+        _writable << size;
+    }
+    
     _writable << _version;
     NPrivate::TWriteCollector _collector;
     NPrivate::Write<AssignedPartitionsMeta>(_collector, _writable, _version, AssignedPartitions);
diff --git a/ydb/core/kafka_proxy/kafka_messages.cpp b/ydb/core/kafka_proxy/kafka_messages.cpp
index 8b08d98ce472..b68f3cd9ba77 100644
--- a/ydb/core/kafka_proxy/kafka_messages.cpp
+++ b/ydb/core/kafka_proxy/kafka_messages.cpp
@@ -4517,7 +4517,12 @@ i32 TSyncGroupResponseData::Size(TKafkaVersion _version) const {
     if (NPrivate::VersionCheck<MessageMeta::FlexibleVersions.Min, MessageMeta::FlexibleVersions.Max>(_version)) {
         _collector.Size += NPrivate::SizeOfUnsignedVarint(_collector.NumTaggedFields);
     }
-    return _collector.Size + NPrivate::SizeOfUnsignedVarint(_assignmentCollector.Size + 1);
+    auto useVarintSize = _version > 3;
+    if (useVarintSize) {
+        return _collector.Size + NPrivate::SizeOfUnsignedVarint(_assignmentCollector.Size + 1);
+    } else {
+        return _collector.Size + sizeof(TKafkaInt32);
+    }
 }