I am kind of late to the party but I have upgraded one of my throaway development wikis with the usual "git remote update && git merge && php maintenance/update.php" process and after the above succeeded I was nevertheless greeted by:
Fatal error: Class 'Cdb\Reader' not found
exception coming out of includes/cache/LocalisationCache.php on line 1263
It seems that I just forgot to update the "vendor" directory (I am somehow reluctant to run composer due to allow_url_fopen=1) requirement
Would that be reasonable to add some basic external libraries checks to update.php to remind users to update those core components prior to accessing the wiki?
Btw. I think UPGRADE doc does not (yet) mention the new process.
//Marcin