I am following ine previous instructions to upgrade from 2.5.x to 2.5.28 in preparation to upgrade to 3.5. Install, DB steps went fine. 2 package updates were fine, but when I try to do Gantry to 4.1.33, whether through update or install, it throws this error:
Fatal error: Call to undefined method JInstallerPackage::getManifest() in /home1/someuser/public_html/joomlatest/tmp/install_599de020ec6ed/install.php on line 75