You have not changed the PHP version. The version detection is performed by checking the PHP_VERSION constant (set by PHP itself) against '5.4.0' using PHP's own version_compare() function. In so many words, PHP itself tells us that it is version 5.3.28. As you see we don't detect the PHP version, we ask PHP itself to tell us which version it uses. Please ask your host to upgrade the PHP version on your site.
Finally do note that even if you upgrade your site's version of PHP your CRON jobs will still be running under an older PHP version until you change the path to the PHP binary (the first part of the CRON job's command line which looks like /usr/bin/php). If that's the case you need to ask your host to give you the correct path to the PHP 5.4 or PHP 5.5 CLI (not CGI/FastCGI!) binary on your server.
Nicholas K. Dionysopoulos
Lead Developer and Director
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