I need a VPN app developer

I need a VPN App Developer to modify apps. I had my own app with VPS servers. Now I need to switch to openvpn free servers.

I have also another app with free openvpn servers. https://play.google.com/store/apps/details?id=com.safervpnapp.androidapp


This is the app with own servers. https://play.google.com/store/apps/details?id=com.ratvpn.app

I need to change my RatVPN app like StrongSafer VPN app.