WPSSO Core is multisite aware and provides settings pages in the network admin interface. You can install WPSSO Core as a "Must Use" plugin (in the mu-plugins/ folder), network activate the plugin, or activate it on individual network blogs (aka sites).
License Management
Premium edition licensing can be managed network-wide by providing an Authentication ID for all network blogs, or an Authentication ID (possibly different ones) can be entered individually in each blog's Premium Licenses settings page.
Please note that the WPSSO Core plugin and the WPSSO Update Manager add-on must be active on the default WordPress blog to get Premium edition updates. This is a requirement of WordPress, not the WPSSO Core plugin. WordPress uses the default blog (ie. BLOG_ID_CURRENT_SITE) to manage updates in the network admin interface, which means the default blog must be licensed to install Premium updates.
Blog ID 1 is usually the default network blog, but this can be changed using a few constants in the wp-config.php file. The default constants provided by WordPress during a multisite network install may look like this (this is only an example - your actual network settings may differ):
define( 'MULTISITE', true ); define( 'SUBDOMAIN_INSTALL', false ); define( 'DOMAIN_CURRENT_SITE', 'example.com' ); define( 'PATH_CURRENT_SITE', '/' ); define( 'SITE_ID_CURRENT_SITE', 1 ); define( 'BLOG_ID_CURRENT_SITE', 1 );
To change the network default blog ID, you must update the BLOG_ID_CURRENT_SITE and PATH_CURRENT_SITE constants for sub-folder multisites, or BLOG_ID_CURRENT_SITE and DOMAIN_CURRENT_SITE for sub-domain multisites (and SUBDOMAIN_INSTALL would be true in that case).