P6X4 moved authority through a bounded cutover and explicit rollback window instead of maintaining two writers that could disagree forever.
#migrations
Z29C stopped interpreting running work through the newest code and gave definitions, steps, adapters, migrations, and receipts stable identities across releases.
X8B6’s browser database could contain the only copy of an inventory action, so a schema upgrade had to behave like a deployment rather than a disposable cache reset.