I just got an email reply from the guys at Cushie Audio,
"Hi Mitch,
Thanks for contacting us.
iOS7 works perfectly with all GROM products. I suspect because you changed phone you need to re-pair your bluetooth, the problem is however you have used up the available BT slots. So you need to reset the GROM BT module. See the following link and read the troubleshooting section:
http://www.cushieaudio.com.au/grom-i3/bluetooth/Try the reset option in the above link and let us know if you have any further issues but that should do the trick.
Kind regards,
Justin"
so, I did and this is how to fix it.
"The GROM unit can only support 2 paired devices. Multiple attempts to pair may cause issues. It must be reset.
Please reset BTD unit:
1. Switch off GROM mode (go to FM for example).
2. Wait for 3-4 seconds.
3. Switch to GROM mode and after 1 second press SCAN, MIX or RPT button.
4. You will hear low beep confirming the reset.
"