MRBS Server failed to set locale to ‘en_GB.UTF-8’ Solution

After migrating Meeting Room Booking System (MRBS) to an Ubuntu 16.04 server with Apache 2.4.18, MySQL 5.7.22, PHP 7.2.7, I got this warning message:

[Warning: Server failed to set locale to ‘en_GB.UTF-8’]

The first thing was to check the locale settings of the Ubuntu 16.04.

$sudo locale -a
C
C.UTF-8
en_US.utf8
POSIX
$

This confirmed that en_GB.UTF-8 is not installed in the system.

Installing the missing en_GB.UTF-8 locale:

$sudo locale-gen en_GB.UTF-8
Generating locales (this might take a while)...
en_GB.UTF-8... done
Generation complete.
$

Check again that installation of locale is successful.

$sudo locale -a
C
C.UTF-8
en_GB.utf8
en_US.utf8
POSIX
$

Checking again the MRBS page, the warning message is now gone.