By now, most probably, we have come in peace with the fact that Angular will be rolling out features using semantic versioning. This means we've got to worry less about nor entirely new concept (at least for now).
Angular skipped version 3 to v4 so as to sync all the different modules. The sync was broken when the Router module was already at v3, and the other modules with no API breaking changes were still at v2. Jacky Kimani announced v4 here at Scotch and highlighted some important points worth noting about this version.
With v4 in RC, there are awesome features that are worth your time. They include but not all:
... read the whole story at scotch.io.