> If the first few versions are v0.1.0, v0.2.0, etc. - how are these handled on the import paths.

This was answered in the post. It's handled in the mod file and not via import path. Import path only changes when there is breaking changes, ie: a major bump and a new /v# for the import path.

Upgrade minor or patch to most recent:

  go get -u

Upgrade patch to most recent:

  go get -u=patch

Upgrade to specific version:

  go get package@version