If not all, at least the latest versions of Encore 5 (and Encore 4 as well, by the way) have always worked “perfectly” on (good versions of) Windows 10 and even 11.
When I say “perfectly”, I mean “as well and as bad as they did when they were released”….
What is true, is that an installed library on one system cannot be just copied to another one, one needs to run an installation file. And since many upgrades were done using online updates, it’s not easy to find a good installation file.
If you send me a mail to andre(.)baeck(at)gmail(.)com, I’ll send you the most recent official build of E504.