phpunit-bridge version(s) affected: 3.4.31

The following code has been added but is not compatible with the supposed minimal version of PHP 5.3:

self::$isAtLeastPhpUnit83 = class_exists(ErrorHandler::class) && method_exists(ErrorHandler::class, '__invoke');

Replace ErrorHandler::class with 'PHPUnit\Util\ErrorHandler'

Please consider adding a Travis-CI build to check the compatibility before tagging version. Maybe just a linting of files to check static syntax compatibility.

If you wish, I could try to add it.