Just by chance I came across the Springshap site and found that on 29 September a new beta version (3.0b4) has been launched which runs on Windows 10 and 11!
Looks to have some new funky options for the engines tab, some of which (high endurance vs high performance engine) does not work yet.
http://springsharp.com/
Its actually made my day that Ian and James are still working on this after so many years!