Complete changelog: https://github.com/AuthMe/AuthMeReloaded/wiki/5.3-Changelog

WARNING:

Use the "spigot" jar only if you are running spigot/paper 1.12!
For 1.7.10, 1.8.8, 1.9.X, 1.10.X and 1.11.X you need to use the "legacy" jar!