They 99.8% don't mean anything and are made up on the spot. Generally speaking, higher means better and/or newer, so numbers go up. 

 No, no we can’t. It’s a secret society and we are sworn to secrecy. 

 i do versioning based on YYYY.MM.

some like semver. 

 SimplySarahv3.1.24.4 

 Most releases are done like this:

Major Release - Minor Release/Patch - Minor patch/Bugfix

So "3.7.5" would be Release 3, Patch 7, Bugfix 5.

This is not universal, but it's a fairly common methodology. Every developer has different ideas about how to do release numbering, so there's no hard and fast rule that governs every project. 

 Could it be one patch and one bugfix? What's the difference between a patch and bugfix?  

 Patches are usually a bundle of bugfixes, bugfixes are small updates that solve single issues.

So a major release is usually a major feature update(s). A major patch is like a group of bugfixes and updates to solve major issues, and bugfixes are usually quick fixes for urgent issues. 

 check out semver.org but it is kinda just made up usually. 

 ty my friend