Change effective on 08 January 2016
The following runtimes are now available for PHP applications on Heroku:
The following extensions are now available for PHP applications on Heroku:
ext-apcuversion 5.1.2 (for PHP 7.0)
ext-mongodbversion 1.1.2 (for all PHP versions)
ext-phalconversion 2.0.9 (for PHP 5.5 and 5.6)
The PHP Support article contains a full list of available runtimes and extensions.