That is false in many ways. The original 3.X was because the MediaVPs originally released in conjunction with SCP for versions 3.6.8-3.6.12. SCP used to be version 3 because the FS1 engine was version 1, the FS2 engine was version 2, so it made sense for the FSO engine to be the 3rd version. SCP now designates versions by year. 19.x, 20.x.
In 2014, FSU wanted to make it clear that our releases were not tied to SCP releases anymore. So we named the version 'MediaVPs 2014' instead of 3.7. Then Knossos came out and version numbers became necessary more standardized for tracking. So MediaVPs 2014 went back to 3.7 while retaining the '2014' in title. Because of Knossos we have stuck with standardized version numbers.
MediaVPs 3.8 was a normal upgrade from 3.7.
Version 4.0 was a major update that included all cannon assets from both FS1 and FS2, so a major version number bump was warranted.
Each release since then has been a normal upgrade getting minor version number bumps only.
MediaVPs 5.0 is slated for whenever the new HD UI is finished... whenever that is.
Since 3.8, FSU has followed a basic versioning scheme.
Major Changes.Minor Changes.Patch
Major == anything that will affect mods in a significant way or major modpack overhauls.
Minor == anything that probably won't affect mods outside of slight balance checks.
Patch == anything that fixes bugs in the current released version. Functionally these versions are equivalent to each other with newer being more stable.