Kirby v2 >> v3 migration problem

Hello guys,

I’m trying to upgrade from v2 to v3. Follow instructions from Kirby manual: 1) remove old /kirby, put new one from the latest release 2) replace index.php and .htaccess with new ones 3) remove /thumbs.
Okay. Then I create upgrade.php file, hit it and got this:

Fatal error: Uncaught Error: Class 'Kirby\Cms\System' not found in /var/www/html/mysite/upgrade.php:8

Same with index.php. What may be the issue? something with composer or what? how can I fix it?

I’ve thought, that it may be a problem because of too much outdated version. So recently I’ve upgraded from Kirby v2.5.5, to the latest v2 release - 2.5.14, uploaded /kirby and /panel folders, and everything working fine.

Thanks a lot, appreciate your help

Where did you put the upgrade script? It must be inside your Kirby project folder next to the index.php/kirby folder.

In a root folder of course.

I attach log from xdebug, but that doesn’t seem to be helpful for me.

How did you install Kirby, via Composer? There seems to be something wrong with the path, because the script is looking in kiritv3/vendor instead of kiritv3/kirby/vendor…

No, I’ve just downloaded latest Plainkit and uploaded it manually, as described in the manual

So, how can I fix it?

Do you happen to have a /vendor folder inside kiritv3?

It is there. From previous installation. Should I remove it or what?

Oh, yeah, I’ve removed it and looks like it moved ahead. Now problems with multilanguage, I will come back with new issues, thank you all!

Multilanguage: Make sure all content txt files have the language extension, e.g. project.en.txt,, even for the default language.