How can one troubleshoot and resolve a "cannot allocate memory" error in Apache log when switching PHP versions on a server?

The "cannot allocate memory" error in Apache log when switching PHP versions on a server can be caused by insufficient memory allocation for the new PHP version. To resolve this issue, you can increase the memory_limit parameter in the php.ini configuration file for the specific PHP version you are switching to.

; Increase memory_limit in php.ini
memory_limit = 256M