I am using a TP Link TL-ER 6120 V1 Router with 1.0.7 Build 20140113 Rel.63736.
I have configured an L2TP VPN on the Router and am able to connect and work with Windows 10 VPN Client, however I am not able to connect using an iOS Device like a Mac Book Pro. I have read on various forums that post iOS 10 there were issues with the L2TP Client however I also read at places that it was fixed by TP Link Support. Unfortunately I was not able to see any link or post that provided the fix. Hence wanted to check in the forum.