That is 3 KB915597 Windows Defender Updates this month; i.e., April 1, April 5 and April 8.
You can see the list of threats addressed by this update and others at this Microsoft site … click <here>.
For a change we seem to be smack up to-date; i.e., there are no newer definitions listed.
But, have a look at the Definition history. It is sobering.
The April 1 update covered Definition 1.79.953.0.
1.79.1432.0 is 18 definitions hence. That is 18 in a week, 2.5 definition sets a day.
Now to be fair the likes of Avast and AVG send out new definition updates daily, if not more often. So if anything one can accuse Microsoft of being dilatory. But then again does anybody really believe that Windows Defender is an industrial strength antivirus/antimalware product? I hope not.
So, that is the state of play. This was the only update today. We will see a barrage next Tuesday, April 13 … the Sinhalese Old Year Day. New Year, logically, is the NEXT DAY, April 14. Happy New Year.