We still compile against java 8 but we run fine on java 11 (or 14). We ship our eclipse product now with Java 13 will upgrade that one to Java 14 for our next release.
To be clear, even if Tycho moves to Java 11 for its own code, it will keep its ability to compile Java code to Java 8 and to build RCP applications that require Java 8. The Java 11 requirement won't propagate to the output of the build.
I guess when we start using Eclipse 2020.09
As far as I understand, right 2020.09 will use Java 11 as minimal Execution Environment.
P.S. i stil wonder how tycho/eclipse is going to work on Java14 now then the pack tools are gone...
For the "provider" part, we probably need to add a guard to the pack200 mojos so they become no-op when no pack200 is found.