The main way to get them is on the Star Wars Trilogy forums, but those have been closed to new members for a while now. You can still get them on public torrent sites, though.
Really? I made a forum account just a few months ago to get 4K77 and 4K83. I haven’t read anything about them closing it for new members recently, so I’m guessing this is something they did temporarily a while ago?
BTW, I very much prefer the 4K77 and 4K83 versions. I used to watch the Descpecialized versions, but now that scans of original prints have been made available I’ll definitely be sticking to those going forward. I get that some people find them to be a bit too grainy, but I’m personally a stickler for authenticity. Plus, I actually really like the grainy film look just in general.