Your requirements could not be resolved to an installable set of packages. Problem 1 - Root composer.json requires composer/class-map-generator == 1.7.1.0 (exact version match), found composer/class-map-generator[1.0.0, ..., 1.7.0] but these do not match your constraint and are therefore not installable. Make sure you either fix the constraint or avoid updating this package to keep the one present in the lock file (composer/class-map-generator[1.7.1]). Problem 2 - Root composer.json requires composer/composer == 2.9.3.0 (exact version match), found composer/composer[1.0.0-alpha1, ..., 1.10.27, 2.0.0-alpha1, ..., 2.9.2] but these do not match your constraint and are therefore not installable. Make sure you either fix the constraint or avoid updating this package to keep the one present in the lock file (composer/composer[2.9.3]). Problem 3 - Root composer.json requires roave/backward-compatibility-check == 8.15.0.0 -> satisfiable by roave/backward-compatibility-check[8.15.0]. - roave/backward-compatibility-check 8.15.0 requires composer/composer ^2.8.12 -> found composer/composer[2.8.12, 2.9.0, 2.9.1, 2.9.2] but these were not loaded, likely because it conflicts with another require. Problem 4 - Root composer.json requires wyrihaximus/test-utilities == 8.6.0.0 -> satisfiable by wyrihaximus/test-utilities[8.6.0]. - roave/backward-compatibility-check 8.15.0 requires composer/composer ^2.8.12 -> found composer/composer[2.8.12, 2.9.0, 2.9.1, 2.9.2] but these were not loaded, likely because it conflicts with another require. - wyrihaximus/test-utilities 8.6.0 requires roave/backward-compatibility-check ^8.15.0 -> satisfiable by roave/backward-compatibility-check[8.15.0]. Use the option --with-all-dependencies (-W) to allow upgrades, downgrades and removals for packages currently locked to specific versions.