I have a website where I\'ve used php to include sections rather than having code be duplicated for each page.
However, recently my webhost upgraded the PHP to 5.6, and
For now the best thing to do is to downgrade to PHP 5.5 or 5.4, because of what CBroe explained in his commentary saying that PHP 5.6 now sets default charset as UTF-8 and many websites are still not ready for it. I had the same issue after migrating to a new server, so I downgraded to PHP 5.5 and automatically all the special characters are displaying correctly again. If you're using WHM, use EasyApache to rebuild Apache and then select the desired PHP version when prompted.
I personally think that PHP developers should warn users better, I mean, making it clear that upgrading to version 5.6 can bring special characters issues for non UTF-8 ready websites/applications. What they did just imposing UTF-8 to millions of developers worldwide was too fast or even too radical.