This is a simple ios app for a VPN connection.
Many thanks to @hamzaozturk for maintaining.
To test the connection I would recommend to lunch your own server. With docker, it is as simple as a run single command. Here is great docker image for that hwdsl2/docker-ipsec-vpn-server.
Deprecated
Credentials for testing you can get after registration in account settings on HidemanVPN site.
At the bottom of the account page you will find: Username, Password, IPSec Pre-Shared Key and servers list like this:
IKEv2 requires address NOT IP. On screenshot "DE97" => input in app "DE97.hmn.me".