i just donwloaded the lasted update and now all my settings are gone, and also i can not select 4K. there is only 2.7K. whats going on?

It has been answered in several posts already, but for some reason when it upgrades it switches the video downlink to the phone/tablet to HD, which disables the recording of 4k for some reason.  Simply go into the settings and find the downlink settings and change from HD to SD and all will be good again.

İs it in the dji app settings or iphone settings?

In App menu (... on the top right corner), HD
Choose the video feedback to your phone to Normal

Did you find it? go to the camera settings and switch it to manual and back to auto it will bring back your 4k.

Lucas775 Posted at 2017-6-11 08:10
Did you find it? go to the camera settings and switch it to manual and back to auto it will bring back your 4k.

yes i did find thanks =) but not the way you mentioned. way of the user above you