Problem with Confluene Upgrade

[Robert M]

I'm trying to upgrade our Confluence environment from v3.5 to v4.0 (eventually, to v5x) and I'm running into a strage error on startup.

The catalina.out file just shows "INFO: Server startup in 1008473 ms"

In the browser I get:

Unable to start up Confluence. Fatal error during startup sequence: confluence.lifecycle.core:pluginframeworkdependentupgrades (Run all the upgrades that require the plugin framework to be available) - com.atlassian.confluence.content.render.xhtml.migration.exceptions.MigrationException: java.util.concurrent.ExecutionException: java.lang.RuntimeException: org.owasp.validator.html.ScanException: java.io.IOException: The character '' is an invalid XML character

I have not been able to find any information on where to look for this error.

[Felipevsw · Accepted solution]

There are some known issues when trying to upgrade from a certain version to another.

What is known to work well is to upgrade from Confluence version 3.5.17 to version 4/5.

So first, upgrade your Confluence 3.5 to the version 3.5.17, then upgarde to version 4.

[Robert M]

We had upgraded to 3.5.13 (from 3.3.3) so I wasn't sure if we needed to go higher at the 3.5 level. I'll download 3.5.17 and do that upgrade first then try the 4 again.

Is there any value of going to 4.0 first or is it safe to go directly to 4.3.7 from 3.5.17??

[Robert M]

Thanks Felipe, by going to 3.5.17 first, I was successfully able to upgrade to v4.3.7

Now the process of finding all the features and functions that no longer work can begin ;)

[Felipevsw]

It's safe to go to the latest version. I've already jumped to the latest 5 version from 3.5.17