Modernize and dropping support for PHP <= 5.4
See http://php.net/supported-versions.php
PHP 5.4 is end of life in 3 months and is in security patch only mode.
With this release we've dropped support for the extendable TestCase
class in favor of using the TestTrait
. The main reasoning behind this is rarely when using mongodb is that the only datastore you are using, and limiting a test case to extending only a mongo based test case will cause headaches (as it did initially for us).
If you still need support for <= 5.4, please stay on the 1.x version.