FPS optimization on mobile devices

Hello, we are scheduled our game launch, and start polishing and optimisation process. We tried:

  • Turn off NavMesh
  • Turn off dynamic lightning
  • Delete objects from scene: particles and heavy material stuff.
  • Turn off Vfx
  • Turn off physics
  • Turn on/off texture and level streaming
    But our FPS doesn’t go high more then 30 fps. So we are empty with ideas about why it’s so. With current material we have 25-28 FPS at IOS and 20-25 at Android, we need to go to 40. Our version is 4.11 and we made migration 2 month ago, before we had 4.09 and our FPS was around 40-45.

Can you give us some advice about why we may have such low FPS after update? and how we can make our FPS higher.