2025-10-19 Release of logback version 1.5.20
• Due to potential vulnerabilities associated with dynamic, i.e. runtime, java code compilation and execution (using Janino), the 'condition' attribute within the <if> element is deprecated and will be removed in 2027.
An online migration service is provided to help with the transition.
The <condition> element, new in this version, admits custom PropertyEvaluator as a recommended alternative. See also the updated documentation on conditional configuration.
• Logback-classic's initialization procedure has been simplified by removing the step instantiating a SerializedModelConfigurator. However, it is still possible to set up SerializedModelConfigurator as a custom configurator.
• A bit-wise identical binary of this version can be reproduced by building from source code at commit 930fb15 associated with the tag v_1.5.20. Release built using Java "21" 2023-10-17 LTS build 21.0.1.+12-LTS-29 under Linux Debian 11.6.