UPDATE:
Cyberpanel is in control of PHP assignments within this Google Cloud Platform Marketplace VM instance of Openlitespeed using WordPress and running Ubuntu 18.04.1.
Once logged in to Cyberpanel, hit Dashboard on the left-hand column. Click dashboard. PHP is among the selections. From there you select which version is most appropriate.
There is an extension the will indicate what most recent PHP version is suitable for each plugin. Choose carefully.