just one top-level version

[constantinpape]

currently we have the version distributed because we initially thought to version individual parts of the spec.
But this is too complicated and we should switch to a single top-level version string.

[sbesson]

Would this single versioning apply only to a given hierarchy level e.g. the multiscales image should have a top-level version that applies to multiscales, omero... or would it be globally be defined and be applicable across multiple levels (plate, well, labels)?

[constantinpape]

Would this single versioning apply only to a given hierarchy level e.g. the multiscales image should have a top-level version that applies to multiscales, omero... or would it be globally be defined and be applicable across multiple levels (plate, well, labels)?

I think that's the idea. Any thoughts @joshmoore?

[joshmoore]

Based on the current layout and the flexibility provided by Zarr V2, it would likely be better to place the version (i.e. context) per JSON (.zattrs) file. We could potentially say it's like the magic number and so only works at the top of the hierarchy. In V3 there should be a top-level metadata location that we could choose to use.