Detailing downgrading of schema version

[ahus1]

Scenario: write in mixed environment or downgrades.

This is following up on the discussion keycloak/keycloak#9640

[ahus1]

Reading the docs, I found the note in the docs:

For each of the entities [...], the current store version is the entity schema version that the store uses for writing objects.

I tried to add paragraphs and change one line to highlight:

• the schema downgrading scenario
• that "readability" implies that the data can later be written to the store again even on downgrades without the loss of (significant) information

Please let me know if this is helpful or confusing, and what is missing or could be shortened.

Thanks!

[sguilhen]

I personally think the suggested changes properly convey what was discussed and to me they make the document clearer.