New apps stop falling back to Marshal for signed messages, the local secret file is no longer world-readable, and SQLite finally renames columns the way the database intended. Here’s what’s new in Rails: Default config.active_support.message_serializer to :json for 8.2 With config.load_defaults 8.2 , messages from MessageVerifier and MessageEncryptor no longer fall back to deserializing Marshal payloads. That covers signed IDs, signed GlobalIDs, Active Storage keys, and the rest.