https://support.microsoft.com/en-us/topic/items-are-held-unnecessarily-in-the-discoveryhold-folder-in-exchange-server-2013-77bf26b6-2d39-4ab5-bc1b-9337ed21e038
Fixes an issue in which items are held unnecessarily in the DiscoveryHold folder after the In-Place Hold expires in Exchange Server 2013.
itemsheldfolderexchange
https://support.microsoft.com/en-au/topic/can-t-view-online-user-free-busy-status-in-exchange-server-2019-and-2016-aa0b6b33-c31a-14aa-5d00-293150eb8d84
Can't view Online user free/busy status in Exchange Server 2019 and 2016
view onlineuserfreebusystatus