I have a question about possible-missing firmware and i wonder how do i download the missing firmware another question how do i upgrade from Zorin 15.3 to Zorin 16 because i have a very old base and maybe i need to switch to Focal and how do i do that?
There will be 15,3 to 16 upgrade path which will be issued before the end of this year. (While many people on this forum advocate a clean install rather than upgrade).
Like on Ubuntu do-release-upgrade?
I suspect something like that. But I've never done "in-place" upgrade myself. Other members on this forum might have a better idea.
This is supposed to be available some time after the official release of Zorin 16. Since this is their first attempt to provide upgrade capabilities you should back up your information before attempting. Zorin group is renowned for testing thoroughly before releasing to eliminate as many bugs as possible before the public has a chance to use their software, but that doesn't mean they will catch all of them and it is possible you may have issues.
Watch Twitter and this forum for updates of impending release announcements.