Multitasking - FileBrowser can be "slide-overed" (like all apps on iPad) but when I'm for example looking web via Safari and I want display FileBrowser in slide-over menu, FileBrowser is missing. Split View is not working too. My device is split-view capable, I use it usually (iPad Air 2, iOS 9).
They confirmed that a provisioning flag was not set correctly when submitting which caused multitasking to not work. I have 7.5 Beta and multitasking works fine. Wait a few days as they submitted a new version waiting to be approved.