There are tags for rstan releases (e.g. there's a v2.19.2 tag) but on GitHub the last release is listed as v2.8.0 from 2015. GitHub is changing their webpage layout for repos and now it says prominently "Latest release v2.8.0 on September 28, 2015" (see red circled area in screenshot below).
For future rstan releases a release should be both tagged and actually "released". This is good practice in general but especially when GitHub now advertises the latest release date on the main repository page:
I removed the "Latest release" section from the RHS of the rstan GitHub page because it's a bad look and confusing to have it say the last release was 2015.
There are tags for rstan releases (e.g. there's a v2.19.2 tag) but on GitHub the last release is listed as v2.8.0 from 2015. GitHub is changing their webpage layout for repos and now it says prominently "Latest release v2.8.0 on September 28, 2015" (see red circled area in screenshot below).
For future rstan releases a release should be both tagged and actually "released". This is good practice in general but especially when GitHub now advertises the latest release date on the main repository page: