The Apache Pulsar team is proud to announce Apache Pulsar version 5.0.0, the new long-term support (LTS) release.
Pulsar is a highly scalable, low latency messaging platform running on commodity hardware. It provides simple pub-sub semantics over topics, guaranteed at-least-once delivery of messages, automatic cursor management for subscribers, and cross-datacenter replication. Apache Pulsar 5.0 LTS: Scalable Topics and Faster Existing Workloads Scalable Topics are a new kind of topic that grows and shrinks with demand while preserving per-key ordering, so applications no longer have to choose a partition count up front. They come with a new Java client API (v5), a language-neutral client specification for all SDKs, and Oxia as the recommended metadata store for new clusters. Pulsar 5.0 also brings major performance and reliability improvements for the topics and applications you already run. For example, on topics with a large number of producers publishing small, non-batched messages at a high rate, consumers now keep up with the producers instead of falling behind. Reliability fixes cover geo-replication, subscriptions, delayed delivery, and acknowledgment recovery. You can upgrade a 4.0.x or 4.2.x cluster to 5.0 and keep your existing topics, the existing Java client (now called the v4 client), and ZooKeeper. The improvements apply without application changes, and you can adopt the v5 client API, Scalable Topics, or Oxia later, on your own schedule. Blog post: https://pulsar.apache.org/blog/2026/10/05/announcing-apache-pulsar-5-0/ Release highlights and upgrading: https://pulsar.apache.org/docs/5.0.x/release-highlights/ Upgrading to Pulsar 5.0.x: https://pulsar.apache.org/docs/5.0.x/administration-upgrade-to-5.0.x/ Java client dependency configuration: https://pulsar.apache.org/docs/client-libraries/java-dependency-configuration/ Downloads: https://pulsar.apache.org/download Release notes: https://pulsar.apache.org/release-notes/versioned/pulsar-5.0.0/ We would like to thank the contributors that made the release possible, and everyone who tested the 5.0.0-M1 and 5.0.0-M2 milestones and shared feedback. Regards, The Pulsar Team
