OpenVPN security update
OpenVPN (the upstream project, not the Android app) has undergone a security audit recently, which resulted in some problems fixed in a new release, 2.4.2. The OpenVPN binary used in the F-Droid build is:
OpenVPN 2.5-icsopenvpn [git:HEAD-53e588afe9fe4500] android-14-armeabi-v7a [SSL (OpenSSL)] [LZO] [LZ4] [EPOLL] [MH/PKTINFO] [AEAD] built on Dec 30 2016
So it's way before the audit results.