This has been forced on Opera by Chromium dropping XP and Vista support, (Google Chrome has gone the same way).
Vivaldi will have to drop XP support as well sooner rather than later I'm afraid for the same reason.
That will only leave Firefox as a currently updated browser still working on XP, and how long that will last is anyone's guess.
Understandable but annoying for those of us who still prefer to stick with XP for whatever reason.
One consolation is that Opera have said that they will continue to provide security patches for Opera 36 for those who can't use later versions, but of course no new facilities will be added.
That's more than Google have done!
;_;
