IKEv2 (Internet Key Exchange version 2) is a secure VPN protocol created many years ago and has the benefit of running closer to your network hardware than other protocols like OpenVPN which runs in user-space like regular applications. Because of this, IKEv2 offers the fastest connection times and high speeds on most networks and it is often supported natively in operating systems, which makes it seamless to use.
One downside of IKEv2, though, is that it is only used on Port 500 which makes it easier to block by network administrators as they can simply block Port 500 on the network and IKEv2 won't connect anymore. But this is why we also offer a handful of other protocols that work on common ports which will usually not be blocked.
If you would like to use IKEv2, you can enable it in the desktop and mobile Windscribe apps by going to Preferences > Connection and setting the Connection Mode to Manual. Then select the IKEv2 Protocol.