It's most like going from http to https in that it changes the fundamental systems beneath it resulting in having stronger keys, longer keys, composed with different tech. You notice the new onion addresses are much longer, and created differently, this is that change.
Unlike IPv4 IPv6, there isn't an authority name service to advertise both connectable addresses. This makes discovery for the end user an explicit action.
If they cannot connect on V2, the method to discover v3 is almost definitely out of band and potentially in the prone to hijacking.
I thought there was some meta tag you could stick in your page's HTML that said what its onion address was; couldn't you just add that with the v3 onion address and clients connecting over v2 would see it and switch over just as if they'd started from non-TOR?
So it would be best if those services simply advertise their new address on the v2 domain right? Rather than sit still and lose their traffic when everyone's forced to, or when attacks really become feasible.
It's not even a hard upgrade, afaik it's literally just a change of what address users have to copy/bookmark and nothing else. I just don't get what the reason to not upgrade is.
Sure, but that's not effort on the site's behalf so they can switch over and make the V2 show the redirect notice. If IPv6 would have been this simple, just show a redirect, we'd have upgraded long ago...
