Specifically, Microsoft will suspend C and D updates, which are usually released during the third and fourth week of each month, respectively. These include non-security improvements and fixes. But the changes don't go into effect until May, so we can still expect a few last optional non-security releases next month.

Microsoft will release its monthly security (B) updates as planned on the second Tuesday of each month, aka Patch Tuesday. We are already waiting for updates to fix two critical zero-day vulnerabilities, which Microsoft disclosed yesterday and that hackers are actively exploiting.

Starting in May 2020, we are pausing all optional non-security releases (C and D updates) for all supported versions of Windows client and server products to prioritize security and keep customers protected and productive. More information here: https://t.co/G5NcWtIiEQ. — Windows Update (@WindowsUpdate) March 24, 2020