Theme does not give minimum PHP version warning

We ran into a problem with the PHP minimum version during a theme upgrade today.
This problem is as described and solved by others in this post:
https://kriesi.at/support/topic/fatal-error-cant-use-function-return-value-enfold-header-php-on-line-6/

However, when this problem arises it can be difficult to describe or understand why the theme suddenly fails.
A minimum version number is an easy thing to test for. (!)
The theme should give a warning in the WP Control Panel if the minimum server specs are not met.
This way a user can identify and then resolve the problem quickly.

Instead we hand almost a day of downtime searching the forums and documentation to try to find the solution.
Regards
~R