Minecraft wiki entry for Version_formats, associated text: Release versions kept the same format as in Alpha, but incremented the phase number to 1. Development versions in this time were known as "alpha" versions (not to be confused with the development phase called "alpha") and took the form of the word "alpha" followed by a four-digit version number (major.minor.patch.revision[6]). The first three digits are the parent version (alpha 1.0.0.1 was a development build for 1.0.0) and the fourth number is the build revision, which is not necessarily incremented by 1 each release.