On Emacs versions targeted by answers
We have no policy on Emacs compatibility of answers, other than the constraint that answers must answer the question. If the question specifies an Emacs version, then answers should work at least on that Emacs version.
If the question doesn't specify any version, answers should make a reasonable assumption. It is generally reasonable to assume that people are running a currently-supported operating system. At the moment, the oldest commonly-available operating systems are:
- CentOS 5 which ships Emacs 21.4, and will be supported until March 2017.
- CentOS 6 which ships Emacs 23.1, and will be supported until November 2020.
- Debian wheezy which ships Emacs 23.4 and will be supported until (probably — Debian's release schedules aren't very predictable) late 2015.
- Ubuntu 10.04 which ships Emacs 23.1 and will be supported until April 2015.
- Ubuntu 12.04 which ships Emacs 23.3 and will be supported until April 2017.
CentOS 5 and Ubuntu 10.04 are mostly used on older servers, and people running them are (or at least should be) aware that they're rather behind the times in terms of software. CentOS 6 and Ubuntu 12.04 are still relatively common, but they are no longer the latest major release of these distributions, so people running them should be aware that they're behind the times and mention that they're running an older version of Emacs in their question. Debian wheezy is still the latest stable Debian release at the time of writing; for Debian stable users, Emacs 23.4 is the current version.
Thus if a question doesn't specify compatibility with older releases as a concern and doesn't concern features that are from more recent versions, arranging for compatibility with Emacs 23.4 is a good thing and should be encouraged. Compatibility with older versions is a lot less useful, I wouldn't bother. Answers that assume more recent versions than the typical audience should mention that fact. In particular, at this point, only very early adopters are running 24.4 or above. If your answer requires 24.4 and the question didn't mention that, your answer has a high chance of not even being useful to the asker, let alone other visitors.
Thus the reason behind this edit was a good one. You may run the latest Emacs version, but not everybody does, and there is nothing virtuous about running the latest version.
Of course, that only justifies edits that do it right. Incorrect edits are never welcome.
If an edit is made to your answer (whether it's a suggested edit or not), you can address a comment to the editor with the
@username syntax (even though the user name won't be available in completion). You can't address users who made suggested edits that were rejected in this way, nor users who reviewed a suggested edit.
You can try to contact anyone in chat. Chat pings will only notify users who have been in the chat room recently enough (you can see who is pingable by typing
@ and looking at the offered completions).