Your requirements could not be resolved to an installable set of packages. Problem 1 - typo3/testing-framework 8.0.0 requires typo3/cms-core 12.*.*@dev -> found typo3/cms-core[v12.0.0, ..., v12.4.16] but it conflicts with your root composer.json require (^11.5). - typo3/testing-framework[8.0.1, ..., 8.2.0] require typo3/cms-core 12.*.*@dev || 13.*.*@dev -> found typo3/cms-core[v12.0.0, ..., v12.4.16, v13.0.0, ..., v13.2.1] but it conflicts with your root composer.json require (^11.5). - Root composer.json requires typo3/testing-framework ^8.0 -> satisfiable by typo3/testing-framework[8.0.0, ..., 8.2.0].