I use Opera-developer as my Internet browser. It is, IMO, the best I have tested. Well, as a "developer" branch, it is "unstable", I mean there are new versions very often.
I don't like very much rolling distros for the sake of being "in the cutting edge" (for this reason I like and use salix

I would like test the last version available by sourcery (59.0.3192.0) and its son opera-developer-ffmpeg-codecs but without uninstall the actual that I have (58.0.3134.0), because in the past I have had problems with codecs. If I do an upgrade, the actual version (which goes well) will be lost.
Any idea?
Thanks for your time.