viben...
Since you asked....
1. The paid version of OpenCPN for Android is based on the
current production release of OpenCPN. Timely upgrades for enhanced features, bug fixes, device support, etc. are available for download from the PlayStore as they become available. The most recent version was published in Feb, 2017.
The free version of OpenCPN on the PlayStore has no upgrade
history, and is based on a version of OpenCPN more than a year old.
2. The paid version of OpenCPN for Android offers unlimited high-priority support on a dedicated forum hosted by the OpenCPN Lead developer.
The free version of OpenCPN on the PlayStore appears to offer no dedicated support channel, or specific support of any kind.
Dave