[FEATURE] Re-developed whole Theme Options backend module with TYPO3 core's constant [FEATURE] Introduce Others features in the Theme Options backend module [FEATURE] Introduce support of EXT:mask v8.x [FEATURE] Introduce support of EXT:container v2.1 [FEATURE] Authentication license hook for EXT:ns_license [TASK] Compatibility with TYPO3 v12 [TASK] Compatibility with PHP v8.1 & 8.2 [TASK] Compatibility drop of TYPO3 <= v11 [TASK] Compatibility drop of PHP <= v8.1 [TASK] Compatibility of MariaDB 10.3+ / MySQL 8.0+ [TASK] Compatibility of Composer >= 2.1 [TASK] Removed EXT:gridelements [TASK] Compatibility of Bootstrap v5 (for Backend Modules & Preview) [TASK] Removed deprecated and breaking changes code [TASK] Improve backend preview CSS/JS [TASK] Improve license authentication for premium TYPO3 templates [TASK] Support Modern browsers with the latest and second latest version [TASK] Improve the Backend module by hiding the page tree [RELEASE] Major breaking changes v12.0.0