The lmms/ZynAddSubFX repo was originally created as a way to use git submodule to isolate the Zyn integration code with lmms' own code.

The repository has not been updated since December 2014 as there is little incentive to... We don't currently use git submodule in our repository, due to some initial complaints by developers when it was originally implemented so we end up making any patches directly to the bundled version, like the rest of our plugins.

The plugin version of this has had quite a few minor changes ranging from 2014 to 2017 and stands as our best version of th Zyn 2.4 integrated code.

Several efforts to migrate to Zyn 2.5 were performed. It was close, but no attempts were 100% successful. More information on that effort here: LMMS/lmms#1860

As an artifact of that effort, the best version of Zyn 2.5 integration dosn't live in lmms/zynaddsubfx but rather lives in @curlymorphic's fork of lmms/lmms, last updated in 2015.

Since then, Zyn 3.0 has been released with a brand new UI which is partly non-free. I'm not sure how this shapes the future of Zyn integration into LMMS.

Future versions/integration efforts should eventually move back to a git submodule or perhaps git subtree as proposed here by @lukas-w: LMMS/lmms#296.

Anyway, I think we can safely delete the existing ZynAddSubFX fork and leave it inlmms/plugins for now. Any objections, please speak up.