Multi touch not working on iOS (does work on Android)

For an interactive experience I'm creating in Unity I wanted to add a simple zoom in/out using the users touch screen (or scroll wheel on PC). This works as expected on Android:

 if (Input.touchCount == 2 && (Input.GetTouch(0).phase == TouchPhase.Moved || Input.GetTouch(1).phase == TouchPhase.Moved))
         {
             if (!resetTwoFin)
             {
                 finDeltaDistance = Vector2.Distance(Input.GetTouch(0).position, Input.GetTouch(1).position) - Vector2.Distance(oldPosFin1, oldPosFin2);
             }
 
             mainCam.fieldOfView -= finDeltaDistance * 0.2f;
 
             if (mainCam.fieldOfView > 80)
             {
                 mainCam.fieldOfView = 80f;
             }
             else if (mainCam.fieldOfView < 20)
             {
                 mainCam.fieldOfView = 20f;
             }
 
             oldPosFin1 = Input.GetTouch(0).position;
             oldPosFin2 = Input.GetTouch(1).position;
 
             resetTwoFin = false;
         }
         else
         {
             resetTwoFin = true;
         }

But it doesn't work on iOS. On iOS the app only seems to recognise one finger at the same time. After crawling over the web for hours I've found this as a solution (placed in a Start coroutine):

 yield return new WaitForSeconds(2f);
 
         Input.multiTouchEnabled = true;

But it doesn't change anything. In Xcode multi touch is also set to 'YES', so that seems to give no problem either. Just to be sure I've also tested if it does work when I set multi touch to false (or 'NO' in Xcode), but this also doesn't change anything...

As I feel like I'm not getting anywhere after the hours I've already spent on this issue, I really hope someone is able to guide me towards a solution.

(using Unity 5.4 RC1)