Need support to upgrade Kirby 3.5 to 3.8

Hi everyone!

I created a kirby website for a friend, which is hosted on a german webspace provider. He was pretty happy with his website and the panel options, although he doesn’t have a clue how kirby works.
So far so good. The website ran like a charm and my friend didn’t ask me for help for a while.

His kirby website runs with version 3.5 (without any plugins). Unfortunately the webspace provider decided to charge for the current php version (8.0). kirby 3.5 seems one of the latest version, which doesn’t support PHP 8.1, 8.2 etc. The following versions PHP 8.1, 8.2 and 8.3 are free though I thought I can help him to update his kirby version.

I decided to keep the update process simple and looked for the next following version which supports 8.1. As far as I know it’s kirby 3.8. (Let me know if I am wrong). My friend doesn’t have a budget so I thought I will not update to a all new kirby version and stick to 3.8 – but I am lost here: As soon as I replace the kirby folder on the website and change the PHP Version I get a lot of errors. I have scrolled through the “Breaking changes”-section of 3.8 but cannot really detect which of these changes are relevant for me.

Here is a stack of errors I get as soon as I update php to 8.1 and replace the kirby folder to 3.8:
http://daniel-plath.com/daten/querfeld/Kirby_Debugger.html

I am not working often with kirby so maybe I am doing something fundamentally wrong. Do you have any suggestions how to handle this situation?

Help is much appreciated. Thanks!

Try to update version by version and see when something breaks

By the way, the latest v3 is Release 3.9.8 · getkirby/kirby · GitHub or Release 3.10.0 · getkirby/kirby · GitHub if you need PHP 8.3