Apache Iggy 0.9.0 Brings VSR Clustering to Standard Server

Maintainers of Apache Iggy have released version 0.9.0, moving Viewstamped Replication Revisited consensus into the message-streaming project's standard server. Piotr Gankiewicz, Apache Iggy founder and PMC member, and Hubert Gruszecki, PMC member, detailed the release in a blog post published on 21 September 2026. It is Iggy's first release since the project graduated from the Apache Incubator on 19 August 2026.

Version 0.9.0 replaces the earlier experimental clustered-server path with the standard iggy-server binary. Single-node operation remains the default, while clustering is enabled through configuration. A three-replica deployment can continue operating with one replica unavailable, and the release introduces separate replicated and persisted durability policies for topics. Existing deployments face a significant upgrade boundary: 0.8.x data directories cannot be migrated, 0.8.x clients and 0.9.0 servers use incompatible wire protocols, and several server configuration options have changed.

The release also introduces Iggy's first PHP SDK, implemented as a native PHP extension in Rust and wrapping the project's Rust SDK. It provides synchronous access to streams, topics, messages and consumer groups through the apache/iggy-php package definition, although it is not yet published to a package manager and currently has to be built from source. Apache Iggy reports more than 600 merged pull requests from 60 contributors in the release, alongside eight new connectors, broader SDK updates and early groundwork for a Kafka protocol gateway.