# Differences between OPC server in version 7.7 and 7.8 **URL:** \ **Category:** Module Development\ **Created:** [April 26, 2016, 5:15pm UTC](https://forum.inductiveautomation.com/t/differences-between-opc-server-in-version-7-7-and-7-8/11582 "2016-04-26T17:15:26Z")\ **Posts on this page:** 4\ **Page:** 1
**Author:** ![PRAMANJ](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/pramanj/32/66935_2.png) [@PRAMANJ](https://forum.inductiveautomation.com/u/PRAMANJ)\ **Post date:** [April 26, 2016, 5:15pm UTC](https://forum.inductiveautomation.com/t/differences-between-opc-server-in-version-7-7-and-7-8/11582/1 "2016-04-26T17:15:26Z")
Hi, I find that the tag path for OPC tags (expose option set to true) in 7.7.8 is for example "ns=2:s=[System]Gateway/Redundancy/IsActive" where as in 7.8 it was "ns=2;s=[System]Gateway/Redundancy/IsActive" (the : instead os ; after ns=2). Also in spite of changing ; to : in my tag paths, the OPC client returns null (tag not found) for all tags! Are there any major changes between version 7.7 & 7.8? regards prafull ---
**Author:** ![PRAMANJ](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/pramanj/32/66935_2.png) [@PRAMANJ](https://forum.inductiveautomation.com/u/PRAMANJ)\ **Post date:** [April 27, 2016, 3:59am UTC](https://forum.inductiveautomation.com/t/differences-between-opc-server-in-version-7-7-and-7-8/11582/2 "2016-04-27T03:59:55Z")
The issue was related with CD-KEY having OPC UA permissions on it. Its resolved now. So there are no changes as far as OPC UA version 7.7 & 7.8 are concerned! Thanks a lot. regards prafull ---
**Author:** ![PRAMANJ](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/pramanj/32/66935_2.png) [@PRAMANJ](https://forum.inductiveautomation.com/u/PRAMANJ)\ **Post date:** [April 27, 2016, 6:42am UTC](https://forum.inductiveautomation.com/t/differences-between-opc-server-in-version-7-7-and-7-8/11582/3 "2016-04-27T06:42:49Z")
Although OPC UA server is running and OPC Client is able to access the tags, but I keep getting following warnings in the log file of Ignition. The log file keeps growing by a KB or so per second! How to stop these warning? INFO | jvm 1 | 2016/04/27 12:08:23 | WARN [ReadService] [12:08:23,675]: Returning ServiceFault for request: com.inductiveautomation.opcua.types.messages.ReadRequest@660c8fe8. StatusCode=StatusCode[Severity=Bad, Subcode=Bad\_SessionIdInvalid] INFO | jvm 1 | 2016/04/27 12:08:23 | WARN [OpcUaConnection[Ignition OPC-UA Server]] [12:08:23,676]: Error reading server time and state: ServiceFault: StatusCode[Severity=Bad, Subcode=Bad\_SessionIdInvalid] INFO | jvm 1 | 2016/04/27 12:08:23 | StatusCode[Severity=Bad, Subcode=Bad\_SessionIdInvalid]: ServiceFault: StatusCode[Severity=Bad, Subcode=Bad\_SessionIdInvalid] INFO | jvm 1 | 2016/04/27 12:08:23 | at com.inductiveautomation.xopc.client.stack.TCPClientChannel.validateResponseType(TCPClientChannel.java:832) INFO | jvm 1 | 2016/04/27 12:08:23 | at com.inductiveautomation.xopc.client.stack.TCPClientChannel.receiveMessage(TCPClientChannel.java:793) INFO | jvm 1 | 2016/04/27 12:08:23 | at com.inductiveautomation.xopc.common.stack.UAChannel$1DeliverMessage.deliver(UAChannel.java:967) INFO | jvm 1 | 2016/04/27 12:08:23 | at com.inductiveautomation.xopc.common.stack.UAChannel$DeliverToDelegate.run(UAChannel.java:1599) INFO | jvm 1 | 2016/04/27 12:08:23 | at com.inductiveautomation.xopc.client.stack.SerialExecutionQueue$RunnableExecutor.execute(SerialExecutionQueue.java:100) INFO | jvm 1 | 2016/04/27 12:08:23 | at com.inductiveautomation.xopc.client.stack.SerialExecutionQueue$RunnableExecutor.execute(SerialExecutionQueue.java:97) INFO | jvm 1 | 2016/04/27 12:08:23 | at com.inductiveautomation.xopc.client.stack.SerialExecutionQueue$PollAndExecute.run(SerialExecutionQueue.java:75) INFO | jvm 1 | 2016/04/27 12:08:23 | at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) INFO | jvm 1 | 2016/04/27 12:08:23 | at java.util.concurrent.FutureTask.run(FutureTask.java:266) INFO | jvm 1 | 2016/04/27 12:08:23 | at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$201(ScheduledThreadPoolExecutor.java:180) INFO | jvm 1 | 2016/04/27 12:08:23 | at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:293) INFO | jvm 1 | 2016/04/27 12:08:23 | at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) INFO | jvm 1 | 2016/04/27 12:08:23 | at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) INFO | jvm 1 | 2016/04/27 12:08:23 | at java.lang.Thread.run(Thread.java:745) ---
**Author:** ![PRAMANJ](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/pramanj/32/66935_2.png) [@PRAMANJ](https://forum.inductiveautomation.com/u/PRAMANJ)\ **Post date:** [April 27, 2016, 10:28am UTC](https://forum.inductiveautomation.com/t/differences-between-opc-server-in-version-7-7-and-7-8/11582/4 "2016-04-27T10:28:10Z")
Problem resolved on installing newly requested OPC UA License key. Please ignore my previous mails. regards prafull