Has a Factory reset been performed after the update was applied. Try that and set up the router from scratch to see if it clears the issue. Don't load any saved configuration files.
Setup DHCP reserved IP addresses for all devices ON the router. Setup/Networking
Ensure devices are set to auto obtain an IP address.
Set Firewall settings to Endpoint Independent for TCP and UDP under Advanced/Firewall.
Enable uPnP and Multi-cast Streaming under Advanced/Networking.
Try single mode G or N or mixed G and N?
If your still seeing issues, then I would recommend downloading v2.03 and apply this version as it was the last most stable version and didn't break Shareport. Thats one item that v2.07 does for those who use Shareport.
Please use the FW update sticky process:
FW Update Process