PHP 8.5 now available
Change effective on 12 December 2025
PHP version 8.5.0 is now available as a runtime version for PHP applications on Heroku.
The following third-party PHP extensions have not yet been made compatible with PHP 8.5 by their respective upstream vendors and are therefore not available:
ext-grpcext-newrelicext-phalcon
The default runtime version for applications that don’t use a composer.json, or where composer.lock contains no requirements for package php even in any dependent package, remains the latest available version of PHP 8.4, unless requirements for extensions constrain resolution to an older supported version.