There is also jackaudio.org version of a2jmidid at GitHub, which served as a safe harbour in cases when suitable LADI version was not available (Thank you!) and could do so again in far future.
Other useful info
a2jmidid is written and supported by Nedko Arnaudov. a2jmidid is based on jack-alsamidi-0.5 (jackd alsa seq midi backend) by Dmitry Baikov.