The new Jetbrains website is pretty nice! BUT, where the heck do you download the non-custom-jdk-bundled versions for OS X now? https://www.jetbrains.com/phpstorm/download/ The only OS X download option (big blue button) is the versions with jdk bundled into the app. (The custom jdk version has always run stupidly slow for me)
If you go to 'Previous Versions' (https://confluence.jetbrains.com/display/PhpStorm/Previous+PhpStorm+Releases), version 9.x is the highest available (but 10.x is the current version).