You are probably thinking of Exchange Online, not on-prem Exchange
On-Prem Exchange client support hasnt changed:
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I seem to recall not so long ago seeing an alert that specific older email clients will be disallowed connectivity to our Exchange servers coming some time in 2022.
Can anyone point me to these alerts if they in fact exist? TIA
You are probably thinking of Exchange Online, not on-prem Exchange
On-Prem Exchange client support hasnt changed: