Plesk update fails on Linux: Public key for plesk-php74-*.rpm is not installed

Symptoms

Plesk update fails with the following error:

CONFIG_TEXT: Fatal error during packages installation: Public key for plesk-php74-snmp-7.4.33-1centos.7.261021.1344.x86_64.rpm is not installed
YumGPGCheckError: Public key for plesk-php74-snmp-7.4.33-1centos.7.261021.1344.x86_64.rpm is not installed

Cause

The issue is tracked as PPPM-15588.

Resolution

1. Connect to the server via SSH.

2. Add PHP 8.3 together with PHP 7.4:

   Note: This installs PHP 8.3 on the server. Do not remove it until the issue is fixed in Plesk, otherwise the error returns on the next update.

   # plesk installer add --components php7.4 php8.3

3. If the update that failed still has packages to install, run it again:

   # plesk installer update