The release of iDeal OS 4.2 is a maintenance update following MX Linux 25.1 and Debian 13.4. Features: AppArmor provides a new containerized environment for the default browser and email client, enhancing online security without sacrificing functionality; OnlyOffice Desktop Editors is the new default office suite; all packages and applications have been updated; Linux kernel updated to version 6.12.74; general system optimization; new activation tool for iDeal OS Diamond edition; anyone who supports our project with a small donation will receive an activation key to unlock all the features of the Diamond edition; there is no need to download or reinstall anything; previously released activation keys will work with the new version of iDeal OS Diamond edition.