ordex wrote
Installing an apk from a third party service is always risky because you don't know if the apk is the official one or it was modified.
That is true - in general. But it is not true if you download an apk directly from the developer (in this case OpenVPN). It would definitely be the official apk.
I'm surprised there is no official apk link. Usually a developer provides such a link so that people can directly use an apk without being routed trough an app store. So i suggest OpenVPN provide such a link.