Now it is time to upgrade D-Link router 850L to new version, 1.12WW.
Here is official download link
Look at the release notes:
1. Update CN channel table
2. Support No-IP DDNS server
1. Fix gmx mail server issue.
2. Fix WAN/LAN IP conflict issue.
3. Fix HW NAT throughput issue
It is only for Hardware version A1.