Your requirements could not be resolved to an installable set of packages. Problem 1 - Root composer.json requires php ^7.4.0 || ^8.0 but your php version (7.1.33) does not satisfy that requirement. Problem 2 - Root composer.json requires sabre/event ^6.0 -> satisfiable by sabre/event[6.0.0]. - sabre/event 6.0.0 requires php ^7.4 || ^8.0 -> your php version (7.1.33) does not satisfy that requirement. Problem 3 - Root composer.json requires sabre/http ^7.0 -> satisfiable by sabre/http[7.0.0, 7.0.1, 7.0.2, 7.0.3]. - sabre/http[7.0.0, ..., 7.0.3] require php ^7.4 || ^8.0 -> your php version (7.1.33) does not satisfy that requirement.