As everybody should know by now, Mozilla did a huge change in the their Firefox release policy.
It is highly controversial, so I felt sharing my thoughts might help.
Until very recently Firefox had a very "old-school" versioning scheme: Major.Minor.Bugfix
Bugfix-releases happened rather often, usually about once a month. Minor releases happened every few months, Major every few years.
I don't need to explain what bugfix releases were for.
Minor releases usually introduced minor new features like support for new web standards, minor UI changes, and bigger improvements on existing features.
Major releases happened very rarely and usually introduced big UI overhauls, major feature additions and support of a bigger range of web-standards.
So what did this mean for support of actual websites and web-applications? I will tell you: Nothing.
Besides adding support for new stuff, there hardly ever were any deprecations and regressions. If your website worked in 1.x, it probably worked just as well in 4.x because the standard didn't change. Maybe it looked a little worse because the standard changed a little, or the implementation behaved a little different.
Let's come to the new and current system, that's meant ...