Redis 4.0.0 GA has been released, featuring a number of new features such as Modules API, improved replication mechanism (PSYNC2), new caching policies, asynchronous deletion operations, microcontroller support, Redis Cluster improvements, and memory management improvements. The Modules API enables developers to extend Redis with new data types, operations, and processes. Additionally, the 4.0.0 release introduces least-frequently-used (LFU) maxmemory policies for improved caching performance and a new MEMORY command for memory introspection.