Does this extension need a release on new grid:code types?

[m-mohr]

The schema allows the newly added grid codes and is generally relatively flexible with that regexp, so the new grid codes are valid under the existing version.

So to avoid too many versions, do we actually need a new version once new grid:code types (such as now Major TOM and EEA) got added?

[jsignell]

Technically the schema didn't change so I don't think you need a new version .The reason to do a new version would potentially be to make it clearer for tooling what the expected values might be? But I don't think there is much value in a new version even for the tooling since essentially either a tool will handle the value or it won't and tools should handle failures gracefully.