tl;dr: After the UK government issued a secret Technical Capability Notice demanding access to iCloud data, Apple withdrew Advanced Data Protection (ADP) for new UK users in February 2025 rather than build a backdoor. However, because ADP can only be toggled by a user's trusted devices, existing users who had already enabled it remain protected, creating a two-tier system where some UK Apple customers have strong end-to-end encryption and others cannot opt in. Apple is now fighting at the Investigatory Powers Tribunal to lift the gag order preventing public discussion of the notice.