get MultiTasking like in iPad on older iPhones, iPads & iPod Touch. If you
aren’t jailbroken yet, Here’s how to jailbreak iOS 9?
Search for ‘MEDUSA’ & install it.
to add source to install this tweak. Source: Xarold Repo (You
need this tweak to use Medusa in landscape mode)
Rotate+ & Enable everything.
another app at the same time.