Your requirements could not be resolved to an installable set of packages. Problem 1 - phpunit/phpunit 4.8.36 requires phpunit/php-code-coverage ~2.1 -> satisfiable by phpunit/php-code-coverage[2.1.0, ..., 2.2.4]. - phpunit/phpunit[5.5.0, ..., 5.5.4] require phpunit/php-code-coverage ^4.0.1 -> satisfiable by phpunit/php-code-coverage[4.0.1, ..., 4.0.8]. - phpunit/php-code-coverage[4.0.1, ..., 4.0.5] require phpunit/php-token-stream ^1.4.2 -> satisfiable by phpunit/php-token-stream[1.4.2, ..., 1.4.12]. - phpunit/php-code-coverage[2.1.0, ..., 2.2.4] require phpunit/php-token-stream ~1.3 -> satisfiable by phpunit/php-token-stream[1.3.0, ..., 1.4.12]. - phpunit/php-code-coverage[4.0.6, ..., 4.0.8] require phpunit/php-token-stream ^1.4.2 || ^2.0 -> satisfiable by phpunit/php-token-stream[1.4.2, ..., 1.4.12, 2.0.0, 2.0.1, 2.0.2]. - phpunit/phpunit[5.5.5, ..., 5.7.27, 6.5.0, ..., 6.5.14, 7.5.0, ..., 7.5.20, 9.0.0, ..., 9.6.17] require ext-xml * -> it is missing from your system. Install or enable PHP's xml extension. - phpunit/php-token-stream[1.3.0, ..., 1.4.12, 2.0.0, ..., 2.0.2] require ext-tokenizer * -> it is missing from your system. Install or enable PHP's tokenizer extension. - Root composer.json requires phpunit/phpunit ^4.8.36 || ^5.5 || ^6.5 || ^7.5 || ^9.0 -> satisfiable by phpunit/phpunit[4.8.36, 5.5.0, ..., 5.7.27, 6.5.0, ..., 6.5.14, 7.5.0, ..., 7.5.20, 9.0.0, ..., 9.6.17]. To enable extensions, verify that they are enabled in your .ini files: - /etc/php/7.4/cli/php.ini - /etc/php/7.4/cli/conf.d/20-curl.ini - /etc/php/7.4/cli/conf.d/20-dom.ini - /etc/php/7.4/cli/conf.d/20-json.ini - /etc/php/7.4/cli/conf.d/20-mbstring.ini - /etc/php/7.4/cli/conf.d/20-phar.ini - /etc/php/7.4/cli/conf.d/20-xmlwriter.ini - /etc/php/7.4/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-xml --ignore-platform-req=ext-tokenizer` to temporarily ignore these required extensions.