Plesk migration warning: The PHP handler 5.5 FPM application (id=fpm) is not available on the destination server. Instead, Plesk will use the following PHP handler: 5.5.38 FPM application served by Apache

Symptoms

• Plesk Obsidian runing on Linux-based operating system
• A message that is similar to the following appears in the Plesk Migrator's Migration results - overall section after pressing Details when migrating a subscription (a similar message may also appear during the restoration of a backup from another Plesk server):
  
  

  CONFIG_TEXT: The PHP handler 5.5 FPM application (id=fpm) is not available on the destination server.
  Instead, Plesk will use the following PHP handler: 5.5.38 FPM application served by Apache (id=plesk-php55-fpm)

Cause

The source Plesk server has many older PHP versions that have not yet been installed on the target Plesk server.
The PHP version mentioned in the error message is installed on the source server and is not installed on the target server, due to which Plesk suggests using another PHP version that is already installed on the destination server.

Resolution

If the websites you are migrating contain scripts that would allow them to properly on the newer PHP version that Plesk will be switching the websites to, this warning message can be safely ignored.

In case the websites require older PHP versions to be present in order to function properly, you should install these PHP versions on the target Plesk server by using the information in these articles:

How to install or remove additional PHP versions provided by Plesk

How to add a custom PHP version in Plesk for Linux?

If the same PHP versions are present on the destination server, you can be sure that the websites will run just as they did on the source server and you can avoid unpleasant surprises.