We recently upgrade from Mediawiki 1.37 to 1.38. ParserOutput appears to be having some trouble with MW 1.38. It looks like SimpleMathJax may be calling the function incorrectly.
Deprecated: Use of ParserOutput::addModules with non-array argument was deprecated in MediaWiki 1.38. [Called from SimpleMathJaxHooks::renderTex in /var/www/html/w/extensions/SimpleMathJax/SimpleMathJaxHooks.php at line 34] in /var/www/html/w/includes/debug/MWDebug.php on line 377
<!DOCTYPE html>
I'm using SimpleMathJax from Git:
#git branch -a *master remotes/origin/HEAD -> origin/master remotes/origin/master
It also looks like SimpleMathJax does not follow Mediawiki conventions of offering branches for REL1_35, REL1_36, REL1_37, REL1_38, etc. So we have to use master.