Hello, we have a very strange problem. The site is <edit: removed> and every single page is displaying the custom 500 page (why the customer edited the 500 page to show this content is another issue but probably not related!).

We suspect the 500 page was edited a while ago as the customer said the content on that page was a year old. The site was fully functional prior to a very recent PHP upgrade, which broke this site only, and no other SilverStripe sites on the same server. They are all version 3.1.12.

**Edit: the PHP upgrade was from 5.4.12 to 5.5.33.**

Worse, even the admin login url is affected, i.e. it too displays the 500 page with no login section to, um log in with, due to the login form not being a part of the template.

Due to the static nature of the error page, we cannot use any debugging techniques.

Also strange is that <edit: removed> displays as per stylesheet, but <edit: removed> displays the menu and heading text differently.

Many thanks in advance.

Update: we decided the problem was from some corrupted file(s) we were never going to find, and are rebuilding the site with a clean installation and manual reconstruction of the database from previously backed up data.

Oh, and the different text displays on the http://www.domain version versus the http://domain version were due to one reading the correct stylesheet and the other reading the default SilverStripe stylesheet in themes/simple/css for some reason :)