On apt update I get:
W: An error occurred during the signature verification. The repository is not updated and the previous index files will be used. GPG error: https://packages.sury.org jessie InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY B188E2B695BD4743 W: Failed to fetch https://packages.sury.org/php/dists/jessie/InRelease W: Some index files failed to download. They have been ignored, or old ones used instead.