Upgrading to 3.5.20 results in a java.lang.AbstractMethodError

In which version was this fixed? I'm running into the same error message described here when upgrading Confluence 5.1.5 -> 5.2.5, though we are running STP 3.5.28.

Hey , Support tools plugin 3.5.20 and above is not compatible with Confluence 5.2.5 series. We fixed this typo in version 3.5.20 as you can see in marketplace:

https://marketplace.atlassian.com/plugins/com.atlassian.support.stp/versions

However in the new releases we can see the compatibility shows for confluence 4.3 which is incorrect . While we address that please, downgrade the add on prior 3.5.20 or upgrade Confluence to 5.3.
Do the upgrade on a staging environment.

Thanks and Regards,
David|Confluence Support Engineer

Hi , thanks for the info. That helps alot I guess. Will give it a try later if downgrading STP works here.

So this actually worked (uninstalling STP 3.5.28 and then reinstalling STP 3.5.10). Afterwards the upgrade to Confluence 5.2.5 worked without any issues. Thanks for the help once again.

In case this is of interest to anybody, I also created a blog about my own experience with this (now resolved) issue including the provided fixes/workarounds in case you run into this: http://www.luke1410.de/blog/?p=57