From time to time, Mozilla discontinues support for an operating system or operating system version. At present, when this happens, users of Firefox on operating systems that are no longer supported no longer get updates and, thus, before long are left with a browser with known vulnerabilities (as new vulnerabilities are virtually inevitably found in due course). Telling the users that there are no updates available or, worse, that "Firefox is up to date" isn't giving the users the information they need to stay secure. As a concrete example, switching compilers to MVSC2010 is going to lead to a situation where systems (Windows 2000 and Windows XP SP1) are left unsupported. However, the relevant update-related bug, bug 682182, seems to be about not pushing incompatible updates but doesn't cover letting the users know that they aren't getting updates because support for their OS ended. It would be much better to let those users know that they are no longer getting security updates than to silently stop providing them. Expected results: Expected the About window to say "Firefox is not up to date, but an up-to-date version is not available for your system. _More information._" when a newer version of Firefox has been released but is not available for the system that Firefox is being run on. ("More information" should link to a Web page that explains the situation in more detail.) When Mozilla knows that there will no longer be updated versions of Firefox for a given operating system, expected Mozilla to push to the affected users something similar to the old "major update" prompt that instead of offering an update explains that none will be forthcoming anymore and that the users need to get a newer system to stay safe.
Wouldn't this be nice to have on the 1.9.2 branch too? Once the last security update from that branch is released, certain Mac users won't receive any further security updates, so it would be nice to inform those users about this.
For the particular case of old Windows XP versions I would suggest telling users that they need to update Windows to SP2 or SP3 rather than saying nothing is available.
Moreover, users running Win2k, XP RTM and XP SP1 could be presented with a browser tab which tells them they're on an unsupported platform, what the risks are, and what to do about it. Agree that we should also add something to the About box, but we shouldn't constrain ourselves to it: probably many users will not look at the About box.
An unsupported message was implemented in bug 843497