As I mentioned in the Github issue, we should move to the following model
* Builds for *old* versions of macOS, should use jack weak linking to work with *old* builds of JackOSX (if they can find it).
* Builds for *newer* versions of macOS, should be built linking to the newer official Jack mac builds. This requires a newer build system and Jack pre-installed.
This is on 10.15.7. I don't have access to other macOS versions rightnow and I fully support being cautious. But contrary to your statementthat JACK1 is more 'compatible', the Pd.app I get from Miller's sitedoesn't run with JACK2, which I believe is what users normally installthese days. The site http://www.jackosx.com mentioned in INSTALL.txtdoesn't exist anymore.