Your requirements could not be resolved to an installable set of packages. Problem 1 - Root composer.json requires php >=7.2 but your php version (5.6.40) does not satisfy that requirement. Problem 2 - league/oauth2-server[5.1.0, ..., 5.1.6, 6.0.0, ..., 6.1.1] require lcobucci/jwt ^3.1 -> found lcobucci/jwt[3.1.0, ..., 3.4.6] but it conflicts with your root composer.json require (4.1.5|^4.2|^4.3|^5.0). - league/oauth2-server[7.0.0, ..., 7.4.0] require php >=7.0.0 -> your php version (5.6.40) does not satisfy that requirement. - league/oauth2-server 8.0.0 requires php >=7.1.0 -> your php version (5.6.40) does not satisfy that requirement. - league/oauth2-server[8.1.0, ..., 8.1.1] require php >=7.2.0 -> your php version (5.6.40) does not satisfy that requirement. - league/oauth2-server[8.2.0, ..., 8.2.2] require php ^7.3 || ^8.0 -> your php version (5.6.40) does not satisfy that requirement. - league/oauth2-server[8.2.3, ..., 8.4.2] require php ^7.2 || ^8.0 -> your php version (5.6.40) does not satisfy that requirement. - league/oauth2-server 8.5.0 requires php ~8.0.0 || ~8.1.0 || ~8.2.0 -> your php version (5.6.40) does not satisfy that requirement. - league/oauth2-server[8.5.1, ..., 8.5.4] require php ^8.0 -> your php version (5.6.40) does not satisfy that requirement. - league/oauth2-server 9.0.0 requires php ~8.1.0 || ~8.2.0 || ~8.3.0 -> your php version (5.6.40) does not satisfy that requirement. - Root composer.json requires league/oauth2-server ^5.1|^6.0|^7.0|^8.0|^9.0 -> satisfiable by league/oauth2-server[5.1.0, ..., 5.1.6, 6.0.0, ..., 6.1.1, 7.0.0, ..., 7.4.0, 8.0.0, ..., 8.5.4, 9.0.0].