This project seems to use JCenter to kept the binary artifacts. However, JCenter (with Bintray) is shuting down rather soon (1st May 2021, with read-only mode starting with 1st Feb), so it would be good to migrate releasing to Maven Central (and possibly synchronize old releases with it). Depending on dependencies in your own project can also be risky :-).
For sample project configuration see: https://github.com/rwinch/gradle-publish-ossrh-sample
And for sync of the old versions: https://www.jfrog.com/confluence/display/BT/Syncing+with+Third-Party+Platforms