Yesterday morning a 31mb update to the game went out that removed addon’s ability to use the /who function.
This has broken quite a few addons.
ClassicCensusPlus
WIM (WoW Instant Messenger)
Some RP addons
and others.
Feel free to add to this list.
Swatter will inform you what the addon tried to access and it will have ()WHO somewhere all over the error report.
To be honest, they don’t want people to actually know how many people are playing. These kinds of addons can very quickly deduce player counts. Probably 75% of the playerbase log in around prime time. Poll every server and you can semi-accurately judge how many people play.
They have to conceal things like this for financial reasons. They don’t want investors seeing a potentially sinking ship.
I have to call bogus on the last two posts.
As the maintainer for both CensusPlus and ClassicCensusPlus, we have never seen any concerns from Blizzard on our tracking of character history in nearly 14 years.
As to the guild invite spam, there has been the ability to block that for quite some time.
while i think that is the real reason (throws tin foil hat on) I also wonder how much the complaint about the spy addon had influence, as that cropped up here in the forums within this last week.
In both WoW and WoW Classic there is a standard interface option to block guild invites.
Go to the system menu, select interface options, under social you can block both Guild invites and Chat Channel Invites.