There's no need to interpret anything. It's spelled out in the list in the Timeline section already. Point 1 tells you it's in Edge. Point 2 tells you that stable will be able to start migrating with 3.23, ie when current Edge becomes stable.
>>Release of Alpine Linux __3.23: [...] From this point onwards,__ users are encouraged to migrate existing installs.
To OP: this announcement from Alpine doesn't contain dates, like you've mentioned. This is apparently not an accident.