# Redundancy problem: Session initialization attempt returned: Bad\_Unsupported("Incompatible software version"). Will retry

**URL:** <https://forum.inductiveautomation.com/t/redundancy-problem-session-initialization-attempt-returned-bad-unsupported-incompatible-software-version-will-retry/54188>\
**Category:** Ignition\
**Tags:** ignition81\
**Created:** [December 16, 2021, 10:05am UTC](https://forum.inductiveautomation.com/t/redundancy-problem-session-initialization-attempt-returned-bad-unsupported-incompatible-software-version-will-retry/54188 "2021-12-16T10:05:37Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![mlunapinel](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/mlunapinel/32/19719_2.png) [@mlunapinel](https://forum.inductiveautomation.com/u/mlunapinel)\
**Post date:** [December 16, 2021, 10:05am UTC](https://forum.inductiveautomation.com/t/redundancy-problem-session-initialization-attempt-returned-bad-unsupported-incompatible-software-version-will-retry/54188/1 "2021-12-16T10:05:37Z")

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Hello!

I’m trying to setup redundancy for my development gateway to run some tests (Using Ignition 8.1.5). I followed the steps on [this guide](https://docs.inductiveautomation.com/display/DOC80/Setting+Up+Redundancy), stablished the gateway connection but the peers never fully connect. On the backup’s logs I can see this message every minute:

`Session initialization attempt returned: Bad_Unsupported("Incompatible software version"). Will retry.`

The master node is running on Windows Server 2016 and the backup node is running on Ubuntu Desktop 20.04. I have also tried using a Windows 10 backup node with the same result. According to the guide, there shouldn’t be any issues with this.

Has anyone encountered this problem?

Thanks

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**Author:** ![Kevin.Herron](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/kevin.herron/32/7259_2.png) [@Kevin.Herron](https://forum.inductiveautomation.com/u/Kevin.Herron)\
**Post date:** [December 16, 2021, 1:27pm UTC](https://forum.inductiveautomation.com/t/redundancy-problem-session-initialization-attempt-returned-bad-unsupported-incompatible-software-version-will-retry/54188/2 "2021-12-16T13:27:36Z")

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There should be a message in your master logs like this:

```auto
The backup node's platform version '%s' is incompatible with the master's version '%s'

```

What does it say? What are the exact versions of each gateway?

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<div class="post-metadata">

**Author:** ![mlunapinel](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/mlunapinel/32/19719_2.png) [@mlunapinel](https://forum.inductiveautomation.com/u/mlunapinel)\
**Post date:** [December 16, 2021, 1:43pm UTC](https://forum.inductiveautomation.com/t/redundancy-problem-session-initialization-attempt-returned-bad-unsupported-incompatible-software-version-will-retry/54188/3 "2021-12-16T13:43:16Z")

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Thanks for pointing that out, master logs are a bit messy 🙂

```
The backup node's platform version '8.1.3 (b2021030309)' is incompatible with the master's version '8.1.5 (b2021042810)'

```

Which is strange because as you can see on the node’s status page, I have installed Ignition 8.1.5…

 ![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/7/5/75b2c584e7b2075359a5365c60b893a9563dbc3a.png)

And I have double checked that the installer that I used was indeed the 8.1.5 version.

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<div class="post-metadata">

**Author:** ![Kevin.Herron](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/kevin.herron/32/7259_2.png) [@Kevin.Herron](https://forum.inductiveautomation.com/u/Kevin.Herron)\
**Post date:** [December 16, 2021, 1:48pm UTC](https://forum.inductiveautomation.com/t/redundancy-problem-session-initialization-attempt-returned-bad-unsupported-incompatible-software-version-will-retry/54188/4 "2021-12-16T13:48:19Z")

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Are you sure the master isn’t pointed at some other 8.1.3 gateway for redundancy? You seem to have multiple remotes.

If that’s not it I’d call support and let them look around.

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<div class="post-metadata">

**Author:** ![mlunapinel](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/mlunapinel/32/19719_2.png) [@mlunapinel](https://forum.inductiveautomation.com/u/mlunapinel)\
**Post date:** [December 16, 2021, 3:18pm UTC](https://forum.inductiveautomation.com/t/redundancy-problem-session-initialization-attempt-returned-bad-unsupported-incompatible-software-version-will-retry/54188/5 "2021-12-16T15:18:05Z")

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Yeah, I have checked multiple times. I will start over once again and if I dont find success I will contact support. Thank you Kevin.