Facebook announced the discontinuation of Account Kit, its app login product, in phases to give developers and partners time to prepare. This archived announcement records the following timeline:
9 September 2019: Account Kit stopped accepting integrations with new apps. Existing integrations continued to work during the transition.
9 December 2019: For SMS phone-number verification, the daily allowance was reduced to a maximum of 1,000 messages per app ID.
9 March 2020: Account Kit became unavailable to developers and partners.
June 2020: Developers and partners had until this stage to retrieve their information from Facebook’s platform unless they had initiated deletion earlier, in which case data remained retrievable for 30 days before deletion.