Symptoms
The option Performance Booster is not available after the update to Plesk Obsidian 18.0.52 under Tools & Settings > General Settings.
Cause
The feature is being rolled out gradually so there is a probability that the feature is not enabled on your installation yet.
Resolution
The feature may be enabled manually.
1.Log into Plesk.
2.Add the following lines to the Plesk panel.ini file:
[ext-performance-booster]
enabled=1
3.Save changes.