Problem:  

Pre-existing IKEv2 VPN mobile configuration scripts do not work with new iPhones.  The script installs the VPN but connection attempts fail.

iPhone7 does not connect to the IKEv2 VPN.  However, older iPhones running IOS8 and IOS9 continues to connect.

Solution:

Update the Mac OS and Apple Configurator 2 software.  Create a new mobile config after software updates are complete.

Explanation:  

IOS 10 cannot connect to IKEv2 VPNs using mobile scripts designed for IOS 8 & 9.

Additional Information:

http://www.stevenjordan.net/2016/11/mobile-config-gui.html

http://www.stevenjordan.net/2016/11/mdm-cert-enrollment.html

http://www.stevenjordan.net/2016/09/harden-rras-ikev2.html