Topic on Project:Support desk

So we just upgraded our MediaWiki to 1.34. After the upgrade, several pages ended up not displaying. When we'd go to edit the page, we found the symbol on the linked example, which I believe is a unknown character in Unicode. This upgrade was from 1.2x something to 1.34, and included an upgrade to PHP. I've tried searching for this but can't find a solution upon search results. The error symbol is below.

https://scan-ne.net/wiki/index.php?title=User_talk:W1KNE/UnicodeError

Here is an example of the change that fixed the page.

https://www.scan-ne.net/wiki/index.php?title=Berkshire_County_EMS&diff=47100&oldid=47049

I believe the previous character was the unicode superscript "1" (U+00B9).

Looks like a character set issue. That question mark in a black diamond character you are seeing is the Unicode replacement character, 0xFFFD (0xEF 0xBF 0xBD in UTF-8). This is exactly what you would see if you entered superscript 1 in ISO-8859-1 (the default for PHP prior to 5.6) and saved it in the database as such, then read it back and tried to interpret it as UTF-8 (the default for PHP from 5.6 on).

Edit the page(s) and restore the correct character now everything is UTF-8 as it should be, and it should work from now on. Otherwise a quick and dirty fix would be to change default_charset back to "ISO-8859-1" in php.ini and revert to the unfixed page(s), but I cannot recommend that.

note mediawiki has been using utf8 in db since mediawiki 1.5, so this is kind of an odd thing to happen