They are currently on the 18.1.0 branch. The latest stable version is 16.14.0 (on 12 Jan 2021). When are you going to create new tags in order to update to the latest version available? Have they forgotten to create tags for each version that has been released or is it simply that the latest versions are not stable?
Note: In the URL Index of /releases there are different versions (currently up to 18.2.0) but the stable version points to version 16.14.0