Hey, team! Let’s try to clarify this a bit. It sounds like you are asking about two separate things.
HAPI key sunset — This applies to the HAPI key a portal formerly had access to for Authorization.
Depreciation of endpoints — this process is not related to the API sunset. Ca you be more specific about which endpoint or set of endpoints you are asking about?
In general, unless explicitly flagged as depreciated all endpoints are considered stable and supported (Legacy and updated endpoints)
The source of truth for changes, updates, and other developer related updates, is the HubSpot Developer Changelog. There are tabs for the latest updates as well as for upcoming changes.