Upgrade of old install 2.4 ----> 2.5

Hi all,
I have one massive deployment that is still running 2.4 (if it ain’t broken do not touch it, approach)
But now I need to integrate to it some LoRa devices that have confusing MQTT API and I desperately need to do transformationPatternOut= in the thing setup.

I found out somewhere here that it is only supported from 2.5 onwards.

I’m not ready to upgrade that to 3.xx as probably that would cause massive problems with all the rules. but an upgrade to the 2.5 should be quite smooth. should it?

That is and Openhabian install running on the Ubuntu and the repos that it used are not there anymore.
What would be the way to do that upgrade manualy? can someone give me a hint on how to procede?

TIA

Are you using the mqtt2 Binding yet? I’m pretty sure that’s required (more than upgrading to 2.5 completely).

The upgrade should not be too hard, but the only option is 2.5.12, no other version is available anymore.

Please be aware that OH3 is about to be cut off, the successor will be OH4.0 (maybe next month?), then there will be no chance to do an upgrade to OH3 any longer and you will face even more problems while upgrade.

As I myself had some hard time by getting from OH1 to OH2 and after some struggling a relative flawless upgrade from OH2 to OH3 (I first got rid of all OH1 bindings, even http - there was a http2 Binding at some point as a beta version)… don’t wait too long.
Rules are easy to convert after getting some basics about Joda Time vs. JavaTime. That’s more or less the only complex part about upgrade from OH2 to OH3 (and you can use search & exchange for some parts)