The first version of AxCrypt was released to the general public on the 19th of November 2001, as a pre-release beta.
Each AxCrypt release has a version number of up to four version levels. The major version is 1, and will remain so until a very large change in functionality is released. At the time of writing this, the current version number is 1.5.3. The changes between versions are documented as a change log and release notes.
Version numbering is a strictly increasing sequence, a higher version number is always a later version.
Interim versions may use the character 'b' for Beta or 'c' for Candidate between the second and third digit, as in 1.5b2.2. This is thus interpreted as beta 2 of the upcoming version 1.5.3.
The change log contains a detailed list of the changes for each release.
The release notes is a more readable summary of the changes.