Thread:Project:Support desk/Extension version numbers not displaying

I've been searching the net for a while now and can't find an explanation for this so apologies if it has already been answered: My MediaWiki version page just has a dash in the field for the version for the 4 skins I have installed and the one extension I have installed SpamBlacklist. Is there a reason/fix for this? It bothers me because I assume there is something bigger going on that is causing it that should probably be resolved. I'm on version 1.25.1 of MediaWiki. Thanks for your time!