luceos Edit; I guess we reused it so that we can add nicknames before completing installation.
Actually it does not make sense. composer update calculates new composer.lock based on current composer.json. composer require --no-update flarum/nicknames adds flarum/nicknames to composer.json without updating composer.lock. And then composer install installs all packages from composer.lock. So with this order flarum/nicknames will not be installed, because you calculated composer.lock before adding this new extension to composer.json.
It should be:
composer require --no-update flarum/nicknames
composer update --prefer-dist --no-dev -a
But in general I would recommend first upgrading your forum with current set of extension, and after that adding new one:
composer update --prefer-dist --no-dev -a
composer require flarum/nicknames --no-dev --update-with-all-dependencies -a
If anything fails after first step, no changes will be saved (composer.json, composer.lock and installed dependencies will not change), while composer require --no-update flarum/nicknames may potentially change your composer.json to non-installable state.
