Hey, I’ve seen this happen before. It usually means there’s an issue with the repository’s signing key or the repo configuration.
A quick way to fix it is to make sure you’ve added the GPG key for that PHP repo and that your /etc/apt/sources.list.d/ entry is correct. You can try running:
wget -qO -
https://packages.sury.org/php/apt.gpg | sudo gpg --dearmor -o /usr/share/keyrings/php-archive-keyring.gpg
And then update the source list to reference the keyring:
deb [signed-by=/usr/share/keyrings/php-archive-keyring.gpg]
https://packages.sury.org/php/ bookworm main
After that, run sudo apt-get update again — it should fix the warning.