Today I had the case that the following message suddenly appeared during an update: The following signatures were invalid: EXPKEYSIG B188E2B695BD4743 DEB.SURY.ORG Automatic Signing Key this was the solution, 1) delete old key: 2) import new key: 3) update package list: The error should be fixed. Thanks to https://www.myprohost.com/en/blog/apt-key-expired-debsuryorg
apt-key expired for deb.sury.org
