During November 2025, Felix Herbst enhanced the Message Formatter in the keycloak/keycloak repository by adding support for SimpleNumber in the MessageFormatterMethod. This update addressed formatting inconsistencies in localization by mapping freemarker.template.SimpleNumber to Java’s Number type, ensuring compatibility with java.text.NumberFormat and preventing runtime errors. Felix focused on improving error handling and code maintainability, consolidating changes around this feature to reduce future regression risk. The work leveraged Java and unit testing to validate reliability, with careful attention to commit traceability and code quality. This targeted enhancement improved message rendering stability in a critical business component without introducing new bugs.