ROS "stable" vs "previos stable"

Probably a stupid question, but… what is the difference between firmware versions described as “stable” and “previous stable” ? E.g. right now the stable one is 3.19 and the previos stable one is the 3.13. Which one should I safetly install in my systems? :confused:

Rgds

well, ‘stable’ means ‘stable for almost everybody’. but if you are very lucky, and have a problem, you still have a choice to use ‘previous stable’ version =)