Deprecated function: usort(): Returning bool from comparison function is deprecated, return an integer less than, equal to, or greater than zero in Drupal\openy_activity_finder\Plugin\Block\ActivityFinder4Block->build() (line 151 of /var/www/docroot/modules/contrib/openy_activity_finder/src/Plugin/Block/ActivityFinder4Block.php)
Ran into this with AF4
Fix as suggested by https://stackoverflow.com/a/65383660/2566038