Timezone offset not supported on older PHP versions

[XedinUnknown]

On versions of PHP prior to 5.5.10, selecting an offset e.g. UTC +5 as the Client Timezone, Fallback Timezone, or WordPress Timezone will result in an exception with the message such as the following, where %1$s is the string representation of the timezone.

'Invalid timezone name: "%1$s"

Cause

On versions of PHP prior to 5.5.10, DateTimeZone::__construct() does not accept offset as argument, but requires specifically the timezone name, such as Europe/London.