Versions

$ nio version
nio 0.1.0 darwin/arm

nio --version gives the same output. The output includes the host platform. A bug report needs this line.

What the number means

Nio is at 0.1. Until 1.0, a release can change the language in ways that break existing code. The changelog  lists the changes in each release.

Version numbers are MAJOR.MINOR.PATCH. Before 1.0, the minor number increases when the language changes, and the patch number increases for fixes.