RailsEventStore 2.19.1 is released as the precursor to version 3.0, introducing deprecation warnings for APIs that will be removed in the next major release. Key deprecations include renaming `in_batches_of` to `in_batches`, `of_types` to `of_type`, a redesigned Projection API that decouples definition from data source, removal of class-based subscribers in favor of instances/lambdas, removal of `EventClassRemapper` in favor of upcasting, and dropping `RailsEventStore::*` constant aliases in favor of `RubyEventStore::*` namespaces. Dispatcher naming is also cleaned up. A notable fix in 2.19.1 addresses a table-locking bug in the PostgreSQL `valid_at` functional index migration — users should use 2.19.1, not 2.19.0. The CI matrix now covers Ruby 4.0, Rails 8.1, Redis 8, PostgreSQL 18, and MySQL 9.7, with EOL versions dropped.
