Your requirements could not be resolved to an installable set of packages. Problem 1 - Root composer.json requires de-swebhosting/typo3-extension-buildtools dev-TYPO3_13 -> satisfiable by de-swebhosting/typo3-extension-buildtools[dev-TYPO3_13]. - de-swebhosting/typo3-extension-buildtools dev-TYPO3_13 requires typo3/testing-framework ^9.0.0 -> found typo3/testing-framework[9.0.0, 9.0.1] but it conflicts with your root composer.json require (dev-main).