Josef Cacek updated the contributing guidelines for the payara/Payara repository, focusing on aligning the build process with the latest Java standards. He revised the documentation to require JDK 21 for building Payara, replacing the previous JDK 11 requirement. This change, implemented using Java and Maven, aimed to reduce build failures caused by outdated instructions and to streamline onboarding for new contributors. By clarifying the build environment in Markdown documentation, Josef addressed compatibility issues and laid the foundation for future Java version upgrades. The work was limited in scope but addressed a concrete need for clearer, more reliable contributor guidance.