Netgear c3700-100NAS xfinity ipv6

I have been using Netgear c3700-100NAS on Brighthouse for 1+ years, without any issues. I am on firmware version 1.01.05 

I recently switched to Xfinity and immediately ran into a problem where the C3700 Modem is unable to pick up an IP address from Xfinity. Uplink / downlink / internet lights are solid green on the modem, and the admin panel shows a solid lock on the cable connection, including minimal data up/down on WAN, but the "internet connection" shows no IP address, no DNS servers, no connection to Xfinity.

Xfinity has triggered reboots multiple times on the device but it has not helped. It turns out that they have provisioned an IPv6 address for this device - something like - 2001.0558.xxxx.0009.xxxx.15ff.fe62.xxxx

I don't see any IPv6 address options in v1.01.05 firmware for c3700 modem. Xfinity says they can't push any firmware update to this device, i.e. they have no such option in their system screens. 

1. Does c3700 support IPv6 WAN connections at all?

2. Would I need a firmware upgrade for this? I've seen some internet posts talking about version v2 firmwares for C3700?

3. How do I get this v2 firmware upgrade, if it's needed? 

Thanks