Your requirements could not be resolved to an installable set of packages. Problem 1 - Root composer.json requires typo3/testing-framework ^8.2.3 -> satisfiable by typo3/testing-framework[8.2.3, 8.x-dev]. - typo3/testing-framework[8.2.3, ..., 8.x-dev] require typo3/cms-core 12.*.*@dev || 13.*.*@dev -> found typo3/cms-core[v12.0.0, ..., 12.4.x-dev, v13.0.0, ..., 13.4.x-dev] but it conflicts with your root composer.json require (14.0.x-dev). Problem 2 - Root composer.json requires typo3/cms-backend ^12.4 || ^13.4 || 13.*.*@dev -> satisfiable by typo3/cms-backend[v12.4.0, ..., 12.4.x-dev, v13.0.0, ..., 13.4.x-dev]. - typo3/cms-backend v12.4.0 requires typo3/cms-core 12.4.0 -> found typo3/cms-core[v12.4.0] but it conflicts with your root composer.json require (14.0.x-dev). - typo3/cms-backend v12.4.1 requires typo3/cms-core 12.4.1 -> found typo3/cms-core[v12.4.1] but it conflicts with your root composer.json require (14.0.x-dev). - typo3/cms-backend v12.4.10 requires typo3/cms-core 12.4.10 -> found typo3/cms-core[v12.4.10] but it conflicts with your root composer.json require (14.0.x-dev). - typo3/cms-backend v12.4.11 requires typo3/cms-core 12.4.11 -> found typo3/cms-core[v12.4.11] but it conflicts with your root composer.json require (14.0.x-dev). - typo3/cms-backend v12.4.12 requires typo3/cms-core 12.4.12 -> found typo3/cms-core[v12.4.12] but it conflicts with your root composer.json require (14.0.x-dev). - typo3/cms-backend v12.4.13 requires typo3/cms-core 12.4.13 -> found typo3/cms-core[v12.4.13] but it conflicts with your root composer.json require (14.0.x-dev). - typo3/cms-backend v12.4.14 requires typo3/cms-core 12.4.14 -> found typo3/cms-core[v12.4.14] but it conflicts with your root composer.json require (14.0.x-dev). - typo3/cms-backend v12.4.15 requires typo3/cms-core 12.4.15 -> found typo3/cms-core[v12.4.15] but it conflicts with your root composer.json require (14.0.x-dev). - typo3/cms-backend v12.4.16 requires typo3/cms-core 12.4.16 -> found typo3/cms-core[v12.4.16] but it conflicts with your root composer.json require (14.0.x-dev). - typo3/cms-backend v12.4.17 requires typo3/cms-core 12.4.17 -> found typo3/cms-core[v12.4.17] but it conflicts with your root composer.json require (14.0.x-dev). - typo3/cms-backend v12.4.18 requires typo3/cms-core 12.4.18 -> found typo3/cms-core[v12.4.18] but it conflicts with your root composer.json require (14.0.x-dev). - typo3/cms-backend v12.4.19 requires typo3/cms-core 12.4.19 -> found typo3/cms-core[v12.4.19] but it conflicts with your root composer.json require (14.0.x-dev). - typo3/cms-backend v12.4.2 requires typo3/cms-core 12.4.2 -> found typo3/cms-core[v12.4.2] but it conflicts with your root composer.json require (14.0.x-dev). - typo3/cms-backend v12.4.20 requires typo3/cms-core 12.4.20 -> found typo3/cms-core[v12.4.20] but it conflicts with your root composer.json require (14.0.x-dev). - typo3/cms-backend v12.4.21 requires typo3/cms-core 12.4.21 -> found typo3/cms-core[v12.4.21] but it conflicts with your root composer.json require (14.0.x-dev). - typo3/cms-backend v12.4.22 requires typo3/cms-core 12.4.22 -> found typo3/cms-core[v12.4.22] but it conflicts with your root composer.json require (14.0.x-dev). - typo3/cms-backend v12.4.3 requires typo3/cms-core 12.4.3 -> found typo3/cms-core[v12.4.3] but it conflicts with your root composer.json require (14.0.x-dev). - typo3/cms-backend v12.4.4 requires typo3/cms-core 12.4.4 -> found typo3/cms-core[v12.4.4] but it conflicts with your root composer.json require (14.0.x-dev). - typo3/cms-backend v12.4.5 requires typo3/cms-core 12.4.5 -> found typo3/cms-core[v12.4.5] but it conflicts with your root composer.json require (14.0.x-dev). - typo3/cms-backend v12.4.6 requires typo3/cms-core 12.4.6 -> found typo3/cms-core[v12.4.6] but it conflicts with your root composer.json require (14.0.x-dev). - typo3/cms-backend v12.4.7 requires typo3/cms-core 12.4.7 -> found typo3/cms-core[v12.4.7] but it conflicts with your root composer.jso