Changelog

Major enhancement

Release 'alpha' dark theme. issue 60924 , pull 4752, issue 62515 , pull 4763, pull 4772, pull 4814, pull 4842, pull 4843, Dark Theme repository, Introducing the Jenkins Dark Theme
Stop supporting .NET Framework 2.0 for launching Jenkins server and agents as a Windows service. .NET Framework 4.0 or above is now required. announcement, upgrade guidelines, issue 60005 , issue 61862 , Windows support policy
Update Windows Service Wrapper (WinSW) from 2.3.0 executable for .NET Framework 2.0 to 2.9.0 for .NET Framework 4.0. Includes numerous improvements and bugfixes. Most notably, the service installer will now ask for permission elevation if the required. changes summary, full WinSW changelog, Windows Agent Installer 2.0 changelog

Enhancement

Show in plugin manager when newer releases of plugins exist but aren't being offered due to unsatisfied requirements. Show warnings for deprecated plugins in the update manager and administrative monitors. pull 4073, issue 59136 , pull 4742, issue 62332
Provide a more modern look and feel for the Jenkins UI. issue 62698 , pull 4808, issue 61973 , pull 4700, issue 62750 , pull 4816, issue 56109 , pull 4820, issue 63002 , pull 4835, Configuration UI Accessibility: Tables to Divs migration, pull 4782, issue 4767 , issue 62175
Remove page generation timestamp from the footer. issue 61806
Allow users with Overall/Manage permission to configure Node Monitoring and to reload configuration from disk. issue 62264 , pull 4724, issue 61458 , pull 4728
Add system read support for 'Node Monitoring Configuration', configuring clouds, viewing agent configuration, system information, and logs. issue 61206
Support Bearer tokens in Jenkins-CLI -auth parameter. pull 4673
Security hardening: Always round-trip password form control values in an encrypted form, even if not backed by an encrypted Secret field. In case of problems, this can be disabled by setting the system property hudson.util.Secret.AUTO_ENCRYPT_PASSWORD_CONTROL to false on startup. issue 61808
Security hardening: Always use a placeholder value for password form control values in item related configuration forms when the user is missing Item/Configure permission, even if not backed by an encrypted Secret field. In case of problems, this can be disabled by setting the system property hudson.util.Secret.BLANK_NONSECRET_PASSWORD_FIELDS_WITHOUT_ITEM_CONFIGURE to false. issue 61808
Update Winstone from 5.9 to 5.10. Update Jetty from 9.4.27.v20200227 to 9.4.30.v20200611. Add --httpsRedirectHttp option that activates automatic HTTP request redirects to HTTPs. pull 4811, 9.4.28.v20200408 changelog, 9.4.29.v20200521 changelog, 9.4.30.v20200611 changelog
Add the ability to filter out environment variables for Shell and Windows batch build steps. issue 62014
Allow fingerprint storage engine to be selected from the configuration page. Add new external fingerprint storage API methods. pull 4834, issue 62345 , pull 4731, JEP-226, Fingerprint API Javadoc, Redis reference implementation
Developer: Add alert-success banner. issue 62747
Developer: Add new extension points to define build step environment filters (currently in beta). issue 62014
Internal: Upgrade to Remoting 4.5. This switches agent.jar and remoting.jar to a code-signing certificate owned by the CDF. pull 4832, Remoting 4.4 changelog, Remoting 4.5 changelog

Bug fix

Fix the default domain name in Windows service serviceaccount configurations. issue 12660 , Windows Service Wrapper 2.7.0 changelog
Fix --httpKeepAliveTimeout option which had no effect (regression in 2.224). issue 61823
Update Stapler from 1.259 to 1.260. issue 61438 , pull 4813, Stapler 1.260 changelog
Fix IllegalArgumentException: Method not found error caused by misbehaviour in Util.isOverridden() (regression in 2.241). issue 62723
Remove the fallback Jenkins URL from the JNLP launch file so that WebSocket agents can be connected over Java Web Start. issue 63014

Changelog for 2.249.1