On 2015-12-08 21:10, Mickey Feldman wrote:
We were (are still) running MW 1.21.1 with PHP 5.3.29. Our host upgraded to PHP 5.5 as default, and will soon discontinue support for PHP5.3.
MW 1.21 was advertised as "requires PHP5.3 or higher". I took that to mean PHP5.5 would not cause any problems.
As soon as the switchover happened, we had a screen full of error messages rather than wiki pages. I set the .htaccess to use PHP 5.3, and we now have a functioning wiki again.
The last point release of MediaWiki 1.21, before that branch stopped receiving patches, was 1.21.11. It's likely that one of the patches after 1.21.1 fixed your problems. (https://phabricator.wikimedia.org/T60640 is a big one I recall from that time.)