The release process is time-based as to roughly every 8 months[1] with X.0, X.1, and X.2 (LTS). This is mostly to communicate which release has long term support.
The deprecation policy[2] is taken very seriously and Django doesn't opt to break things if it can.
Recently there was a very interesting discussion[3] between the Fellows as to whether the version numbering is confusing as this doesn't follow the same pattern as other libraries.
1: https://docs.djangoproject.com/en/dev/internals/release-proc...
2: https://docs.djangoproject.com/en/dev/internals/release-proc...