Major Version . Minor Version . Release . Sub-Release . Vendor Change . . . As a general rule, a Major version change indicates the entire API may have changed. A minor version change indicates additional features, and/or clarification of the API. A release change is a bugfix. API = Application Programming Interface, the way the code talks to other programs/devices. The numbers are distinct/positional. IP addresses represent a 32 bit unsigned binary number x.x.x.x Each number represents 8 bits with a value between 0-255, 10.8.1.1 < 10.108.1.1 numerically, lexically 1.1.... < 1.8... It can however be confusing. Microsloth sorts ip addresses lexically on it's DNS servers. Effing annoying. 10.1.x.x , 10.10.x.x ,10.100.x.x ,10.2.x.x, sh*t. With most things IT numbers separated by '.' indicate positional order not lexical, so 1.100 > 1.25 unless you are referring to an actual real number. YMMV.