Is SiK firmware upstream maintained?

I have a question - Is there or where is the current SiK firmware upstream? The original SiK firmware repository seems to be unmaintained for few years.

  • Have I missed something and SiK firmware was replaced by something newer?
  • SiK firmware users are satisfied with the current state of the development and no new features are needed?

Is there some possibility of how can I help to resolve that? My current personal opinion is the SiK firmware is still relevant for UAV telemetry radio link usage.