OpenVPN Upgrade - CC 15.05 to LEDE

I have not really followed the details, but believe that there have been some changes to both the OpenVPN packages needed and versions of the related tools.

I am planning to upgrade from CC15.05 to the current LEDE and unclear if my older clients (OpenVPN 2.3.6 and OpenSSL 1.0.2a) will still work on an upgraded server?

OpenVPN looks like 2.4.3 and openssl-util 1.02j are the current versions.

Any other hints are appreciated.