It’s very unusual for Microsoft to release Windows 10 patches on a Sunday, but the company did so yesterday for all supported versions of Windows 10. This also includes the upcoming May 2019 Update, as Windows Insiders already running it received the build 18362.116 yesterday.
All these new patches include a single fix for an issue that could prevent users to access some UK government websites using Microsoft Edge and Internet Explorer 11. According to the release notes, the bug was only for gov.uk websites that don’t support HTTP Strict Transport Security (HSTS).
If you’re running Windows 10 version 1809, you should get the build 17763.504 via Windows Update. Windows users still on the version 1803 should get the build 17134.766, and there are also new cumulative updates for the versions 1709, 1703, 1607 1507. Again, all these patches include the same single fix, and all of them also come with minor known issues that will be fixed in an upcoming release.
We remind you that Windows 10 updates that do not include any new security updates (just like the ones Microsoft released yesterday) are entirely optional, but you'll still get this fix if you wait for next month's cumulative "Patch Tuesday" update.