I was a little surprised at first when I saw it, since it's a programming language. It does seem to attract some off-topic questions, but that's not what my question is about. When I looked at the tag wiki, I noticed the excerpt says:
The current version is 5.3.3, released on July 22, 2010.
PHP isn't on hiatus or anything, there have been plenty of new versions since 2010. According to php.net, the current version is 5.6.12, and PHP 7 is in its third beta.
I was going to edit it but then I realized that if I just update the version number, it will have to be changed again soon. I don't spend as much time here on Super User as I do on Stack Overflow, so I'm not sure what the consensus on version numbers in tag wikis is around here, and I couldn't find anything in the help center or on meta.
Should the version number simply be updated?
The current version is 5.6.12, released on August 6, 2015.
That will need to be updated every month when a new bugfix update comes out.
Should it be changed to include just the major version number?
The current major version is PHP 5.
That's practically meaningless because PHP 5 came out a long time ago and each "minor" version number since then has included significant changes.
Should it be changed to include the major and minor version number?
The current version is PHP 5.6.x.
That will need to be updated less often, but it will still need to be updated soon when PHP 7 comes out.
Should it mention PHP 7?
The current version is PHP 5.6.x, and PHP 7 is currently in beta.
The current PHP 5 version is 5.6.x, and the current PHP 7 version is Beta 3.
Or should it not mention the version at all? That leaves the wiki excerpt as just one sentence, but maybe that's OK.
Edit: The Stack Overflow equivalent of this tag does not mention the version number, for what it's worth.