We've brought up a purely fresh 3.6.3 (now 3.6.4) mongo database from scratch. Having tried with 2.5 through 2.6... When attempting to test our connection, in which we simply run a "ping" command when connecting, we're getting the following exception about Timestamp BSON type not being supported:

{{ObjectSerializer does not support BSON type 'Timestamp'.: at }}
{{ MongoDB.Bson.Serialization.Serializers.ObjectSerializer.Deserialize(BsonDeserializationContext context, BsonDeserializationArgs args) at }}
{{ MongoDB.Bson.Serialization.IBsonSerializerExtensions.Deserialize[TValue](IBsonSerializer`1 serializer, BsonDeserializationContext context) at }}
{{ MongoDB.Bson.Serialization.Serializers.DynamicDocumentBaseSerializer`1.Deserialize(BsonDeserializationContext context, BsonDeserializationArgs args) at }}
{{ MongoDB.Bson.Serialization.Serializers.SerializerBase`1.MongoDB.Bson.Serialization.IBsonSerializer.Deserialize(BsonDeserializationContext context, BsonDeserializationArgs args) at }}
{{ MongoDB.Bson.Serialization.Serializers.ObjectSerializer.DeserializeDiscriminatedValue(BsonDeserializationContext context, BsonDeserializationArgs args) at }}
{{ MongoDB.Bson.Serialization.Serializers.ObjectSerializer.Deserialize(BsonDeserializationContext context, BsonDeserializationArgs args) at }}
{{ MongoDB.Bson.Serialization.IBsonSerializerExtensions.Deserialize[TValue](IBsonSerializer`1 serializer, BsonDeserializationContext context) at }}
{{ MongoDB.Driver.Core.WireProtocol.CommandWireProtocol`1.ProcessReply(ConnectionId connectionId, ReplyMessage`1 reply) at }}
{{ MongoDB.Driver.Core.WireProtocol.CommandWireProtocol`1.<ExecuteAsync>d__15.MoveNext() — End of stack trace from previous location where exception was thrown — at }}
{{ System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) at }}
{{ MongoDB.Driver.Core.Servers.Server.ServerChannel.<ExecuteProtocolAsync>d__27`1.MoveNext() — End of stack trace from previous location where exception was thrown — at }}
{{ System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) at}}
{{ MongoDB.Driver.Core.Operations.CommandOperationBase`1.<ExecuteProtocolAsync>d__28.MoveNext() — End of stack trace from previous location where exception was thrown — at }}
{{ System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) at }}
{{ MongoDB.Driver.Core.Operations.ReadCommandOperation`1.<ExecuteAsync>d__2.MoveNext() — End of stack trace from previous location where exception was thrown — at }}
{{ System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) at }}
{{ MongoDB.Driver.OperationExecutor.<ExecuteReadOperationAsync>d__3`1.MoveNext() — End of stack trace from previous location where exception was thrown — at }}
{{ System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) at }}
{{ MongoDB.Driver.MongoDatabaseImpl.<ExecuteReadOperationAsync>d__50`1.MoveNext() — End of stack trace from previous location where exception was thrown — at }}
{{ System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() at }}
{{ System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) at}}
{{ MongoDB.Driver.MongoDatabaseImpl.<UsingImplicitSessionAsync>d__57`1.MoveNext() — End of stack trace from previous location where exception was thrown — at }}
{{ System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() at }}
{{ System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) at }}
{{ System.Runtime.CompilerServices.TaskAwaiter`1.GetResult()}}