Throttling and Blocking Email from Persistently Vulnerable Exchange Servers to Exchange Online

chupacabra_007  Exchange 2016 is in extended support and there are no more fixes (CU23 was the last fix for EX2016) coming for that version of Exchange. There will only be security fixed for EX2016. Microsoft would recommend moving to Exchange 2019 which does not have the problem with pick up folders and is still in support. Next time you don't have the information you need please call support and ask. That said it's also a good move to be on EX2019 because if you plan on moving to Exchange SE (The Next and final version  of Exchange next year) you will need to be on Exchange 2019 CU15 to upgrade in place to Exchange SE. There is no path from Exchange 2016.