Hi Roland,
Yes, in the PB 2021 IDE you will be able to compile for PB 2019 R3 or for PB 2021. This was feature change we made to the IDE to support multiple runtimes starting in PB 2019 R3. Please refer to this table: https://docs.appeon.com/pb2019r3/whats_new/ch01s01s03.html
The projected release is this summer. At this point, can't give you exact date because the final release date will depend on how the current beta cycle goes.
Aside from supporting PowerServer 2021, PB 2021 has a new standalone compiler for doing automated builds called PBAutoBuild. This is documented in the roadmap page so we have delivered exactly what we stated: https://www.appeon.com/developers/roadmap
Compared to previous standalone compiler, it can do some ORCA stuff like getting the source code from source control. But probably its biggest advantage is that it supports the new PowerClient deployment option for client/server, which is really gaining popularity as better way to deploy client/server apps. And of course, it supports PowerServer 2021 compilation. Here is the beta documentation about this new feature: https://docs.appeon.com/pb2021/whats_new/Building_your_PowerServer_project_with_commands.html
Best regards,
Armeen