tl;dr: after the new Reading Lists endpoints are complete, discuss API changes with callers to ensure everything is satisfactory.
I've subscribed some folks from the mobile apps teams to this task. But we're not quite ready for the conversations yet, because the endpoints are still being finalized. Shouldn't be too long now - days or at worst weeks rather than months.
Some changes to endpoint behavior are inevitable as part of reimplementing the Reading Lists endpoints. For example, some error messages include the word "Hyperswitch", which is a RESTBase-related technology that we will no longer be using. These error messages will therefor contain different text in the new endpoints. Some headers may also be sent differently by MediaWiki than by RESTBase.
Additionally, there may be intentional changes to the contract, such as adding parameters previously supported by the Action API endpoints that RESTBase forwarded to but not exposed by RESTBase (limit, etc.) Callers should be made aware of these parameters, in case they wish to make use of them.
Completion criteria:
[] Changes have been documented in a way conducive to a conversation with the. mobile apps teams
[] IOS app team has confirmed they are comfortable with the changes (and/or any necessary code adjustments have been made)
[] Android app has confirmed they are comfortable with the changes (and/or any necessary code adjustments have been made)