This extension is the updated Single Sign On for Flarum extension.
This extension enables Single Sign On (shortly SSO) for Flarum. The workflow is based on this post. The extension is useful if you run Flarum on a subdomain, but you want to use the login mechanism of your main website or SSO system.
composer require maicol07/flarum-ext-sso
More detailed instructions are written here.
composer update maicol07/flarum-ext-sso
More detailed instructions are written here.
Check instructions on the official docs