Let's Encrypt to revoke 3 million certificates on March 4 due to software bug

You should have received an email if one of your certs was affected, but you can always replace your certs just in case. They did say that some of the affected certs they didn’t have a good email contact for, so it’s possible that some of the affected people weren’t notified. Here’s their FAQ if you need more info:

They do have a tool that you can use to check your certs against the issue:
https://checkhost.unboundtest.com/