OpenLiberty, the project behind IBM WebSphere, has released version 19.0.0.1 as its first move into four-week releases.

This schedule enables customers to receive faster bug-fixes and security updates, with the right but not the obligation to take each update. "There is no need to keep current if you do not wish to, although we obviously encourage it," explains Alasdair Nottingham, an IBM contributor to the OpenLiberty project. The four-week schedule, started in February, means that there will be 12 releases in the 2019 calendar year.

OpenLiberty provides a development runtime for standalone applications build using the Eclipse MicroProfile framework. These applications launch as a standalone JAR file, or can leverage the JEP-343 packaging tool for a complete standalone application with no external dependencies or JREs. The Liberty project is lightweight, minimizing the disk and memory footprint. When OpenLiberty was introduced in 2017, it was the first application server to run on a memory-constrained Raspberry Pi, and it also ran on Android phones.

The OpenLiberty getting started guide provides a sample project for building standard web-based REST applications. This guide includes a section to improve development speed, about updating the source code without restarting the server. By using this feature, developers can quickly iterate on their own applications and ideally take updates from OpenLiberty after the four-week release. Services like Dependabot can automatically apply the security updates.

The four week release cadence is faster than similar projects, such as Payara. The Payara release list provides updates between a few weeks or an approximate quarterly basis. Common drivers for software delivery are dates or features. In a date-driven release train, trains are set to leave at scheduled times. Any features that are ready go out on the train. Any features that are not ready either await the next train or enter a specially marked car so that end-users can still evaluate the feature knowing that it is pre-release. A feature-driven release operates similarly, except that the train leaves the station once the key features are on board. With its new four-week cadence, OpenLiberty represents the date-driven model.

OpenLiberty is available to all developers, and runs on OpenJDK and/or OpenJ9. Both runtimes are available from AdoptOpenJDK.