Earlier today, a security patch to the Unity engine was released by Unity, which patches a security vulnerability in games built with the Unity engine. Today's patch updates the game engine to the latest version, 2020.3.49f1 in which this vulnerability has been patched.
For security reasons, I have disabled the builds of the game that were previously available on the legacy branches. I intend to rebuild these versions of the game next week with the patched engine version, but until then those versions of the game will be unavailable. Please note that the legacy-EA25 version is still available as this versions of the game runs on Unity 5.6 which is unaffected by the vulnerability.
For more information about the security vulnerability, please see Unity's message here: https://discussions.unity.com/t/unity-platform-protection-take-immediate-action-to-protect-your-games-and-apps/1688031
EDIT: All legacy branches have now been rebuilt in the 2020.3.49f1 engine version and are safe to use!
/Johan