Global terms removed in WordPress 6.1

Global terms is an old feature from the MU days of WordPress when multisite and single site installs had separate code bases. It has been abandoned and unmaintained for a significant amount of time, and in WordPress 6.1, it has finally and officially been removed. Here’s a brief timeline of events leading up to this change. WordPress 3.0 (2010): Phase 1 The first phase of removing global terms was in WordPress 3.0. The user interface for global terms was completely removed in [14854]. The “on” switch in Core was removed in [14880], though plugins were free to call install_global_terms() directly,

source https://www.worldofwp.com/global-terms-removed-in-wordpress-6-1/