Update

1) Go to the root of your project

cd /var/www/sites/your-site.ru

2) Update

# Composer update to the latest stable version
COMPOSER_HOME=.composer php composer.phar self-update
# Extra plug-ins
COMPOSER_HOME=.composer php composer.phar global require fxp/composer-asset-plugin --no-plugins
# Download dependency
COMPOSER_HOME=.composer php composer.phar update -o
# Clear all caches (Just in case)
php yii cms/cache/flush-all
# Installation of migration
php yii cms/migrate --interactive=0
# Init privilages. If the component is installed skeeks/cms-rbac (optionality)
php yii rbac/init
# Init agents. If the component is installed skeeks/cms-agent (optionality)
php yii cmsAgent/init
# Clear all caches (Just in case)
php yii cms/cache/flush-all

Or all of these commands in one line

COMPOSER_HOME=.composer php composer.phar self-update && COMPOSER_HOME=.composer php composer.phar global require fxp/composer-asset-plugin --no-plugins && COMPOSER_HOME=.composer php composer.phar update -o -n && php yii cms/cache/flush-all && php yii cms/migrate --interactive=0 && php yii rbac/init && php yii cmsAgent/init && php yii cms/cache/flush-all

Or mount it in your settings file composer.json

"scripts": {
        "post-install-cmd": [
            "skeeks\\cms\\console\\Composer::postInstall"
        ],
        "post-update-cmd": [
            "skeeks\\cms\\console\\Composer::postUpdate",
            "php yii cms/cache/flush-all",
            "php yii cms/migrate --interactive=0",
            "php yii rbac/init",
            "php yii cmsAgent/init",
            "php yii cms/cache/flush-all"
        ]
    },

Exemple: https://github.com/skeeks-cms/app-basic/blob/master/composer.json


Alternative commands, depending on the server configuration and your access rights:

#composer if not installed globally, you can use this command
COMPOSER_HOME=.composer php composer.phar
# or use if composer installed globally
composer
php yii
# or use (file yii must be executable)
yii