Sorry for the delay. And by the way, we are not going to change our licensing model any time soon (if ever). This one-time payment + 1 year grace period + discounted upgrades system works well for us and the majority of our customers from what we know. We don't see any reason why we should change it to subscription model other than to squeeze more money from our customers, but this we definitely won't do.
Our mobile client has its own versioning and so far this app is free. We haven't decided yet what licensing model we are going to use for it when we add more significant features to the client (namely, the full-fledged address book). There are different options that we are considering.