We have a fairly new product (v1.x) that is installable software, and which is charged as a once off payment with free upgrades to further 1.x upgrades. There is no 'annual maintenance' construct.
For version 2, we are planning some service components (including web delivery components) which would lend themselves to a more subscription-based model, and provide a neater way of creating plans (eg different segments, multi-user, more resources, more features, etc).
So my question is, from people who have done it (or considered doing it) are there any lessons on how to manage that with your existing customer base, primarily from the perception of "I've already paid up front, so why should I pay again?"
Ideas we have are if you have bought 1.x and want to take up 2.x, you get a (heavily) discounted rate for the first 12 months, etc - but we fear that we're still asking for them to get their CC out again and at the same time committing to a new recurring payment model, so it would be a harder sell than just another $X up front (that they are already used to).