Your lock file does not contain a compatible set of packages. Please run composer update. Problem 1 - charcoal-dev/buffers is locked to version 0.1.0 and an update of this package was not requested. - charcoal-dev/buffers 0.1.0 requires ext-gmp * -> it is missing from your system. Install or enable PHP's gmp extension. Problem 2 - charcoal-dev/gmp-adapter is locked to version 0.0.1 and an update of this package was not requested. - charcoal-dev/gmp-adapter 0.0.1 requires ext-gmp * -> it is missing from your system. Install or enable PHP's gmp extension. Problem 3 - charcoal-dev/buffers 0.1.0 requires ext-gmp * -> it is missing from your system. Install or enable PHP's gmp extension. - furqansiddiqui/bip39-mnemonic-php 0.2.1 requires charcoal-dev/buffers ^0.1.0 -> satisfiable by charcoal-dev/buffers[0.1.0]. - furqansiddiqui/bip39-mnemonic-php is locked to version 0.2.1 and an update of this package was not requested. To enable extensions, verify that they are enabled in your .ini files: - /usr/local/etc/php/conf.d/docker-php-ext-amqp.ini - /usr/local/etc/php/conf.d/docker-php-ext-apcu.ini - /usr/local/etc/php/conf.d/docker-php-ext-bcmath.ini - /usr/local/etc/php/conf.d/docker-php-ext-gd.ini - /usr/local/etc/php/conf.d/docker-php-ext-intl.ini - /usr/local/etc/php/conf.d/docker-php-ext-opcache.ini - /usr/local/etc/php/conf.d/docker-php-ext-pcntl.ini - /usr/local/etc/php/conf.d/docker-php-ext-redis.ini - /usr/local/etc/php/conf.d/docker-php-ext-sodium.ini - /usr/local/etc/php/conf.d/docker-php-ext-xsl.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-gmp` to temporarily ignore these required extensions.