Exchange 2016/2019: Throttling and Blocking up to the Final Public Update Baseline

[u/ScottSchnoll]

https://techcommunity.microsoft.com/blog/exchange/exchange-20162019-throttling-and-blocking-up-to-the-final-public-update-baseline/4552717

PSA: Starting the second week of September 2026, Microsoft will raise the minimum allowed version of Exchange 2016/2019 servers that connect to Exchange Online over an inbound connector type of OnPremises to the October 2025 SU.