Plugin broken in WP Versions < 4.6

In the latest release, you updated functions.php to call the new get_sites() function, and added support for older version of WP in deprecated.php

Unfortunately, the fallback function you added is for get_asites() rather than get_sites(), which causes a fatal php error in WP versions < 4.6, specifically when using the subscription levels ajax.

Updating references of get_asites() to get_sites() fixes the problem.