Your requirements could not be resolved to an installable set of packages. Problem 1 - vimeo/psalm[5.0.0, ..., 5.x-dev] require ext-simplexml * -> it is missing from your system. Install or enable PHP's simplexml extension. - vimeo/psalm[5.0.0-alpha1, ..., 5.0.0-rc1] require php ^7.4 || ~8.0.0 || ~8.1.0 -> your php version (8.2.9) does not satisfy that requirement. - Root composer.json requires vimeo/psalm ^5 -> satisfiable by vimeo/psalm[5.0.0-alpha1, ..., 5.x-dev]. To enable extensions, verify that they are enabled in your .ini files: - /etc/php/8.2/cli/php.ini - /etc/php/8.2/cli/conf.d/20-curl.ini - /etc/php/8.2/cli/conf.d/20-mbstring.ini - /etc/php/8.2/cli/conf.d/20-phar.ini - /etc/php/8.2/cli/conf.d/20-tokenizer.ini - /etc/php/8.2/cli/conf.d/99-pecl.ini You can also run `php --ini` in a terminal to see which files are used by PHP in CLI mode. Alternatively, you can run Composer with `--ignore-platform-req=ext-simplexml` to temporarily ignore these required extensions.