Microsoft
Microsoftluke_q7 - the installation that you have should be a 'regular' Exchange installation; it is simply an on-premises install and you should update it. At this point, we do not have any plans to release fixes for older CUs.
March was the ONLY time that we have done such a thing (and we release security updates often, not every single month but often) - and it was because of active exploits by a particular actor (it was a very unique situation). Released updates for older CUs were not full updates either; those updates only addressed 4 March vulnerabilities. They were not 'cumulative' security updates like we release usually. Please update... Exchange Update Wizard will give you the steps that you need to follow.
