What versioning system is netCDF4 following? It does not seem to be exactly semantic versioning but something like 1.major.minor[.patch]. Is this correct? Or is it major.minor.patch[.bugfix]? Or something in between?

The background to this question is that xarray pins the oldest minor version of a package it officially still supports. We currently pin version 1.5 - but if you don't follow semantic versioning we should probably pin version 1.5.4.