Transition of a mobile app from free to freemium

I'm about to release a mobile app I wrote. Since the first version is somewhat bare-bones (aka a MVP), I'm making it free. However, in the future I want to use the freemium model. Do you think it's OK from the customer's perspective, to give them a free product, and then ask to pay for the features they've been using for free? Or perhaps I shouldn't worry too much because not a lot of people will have the free version to begin with?

Any thoughts/insights are appreciated.

It's perfectly acceptable to change your business model, but definitely be aware of backlash.

Recently Chargify, which makes a Web-based system that small companies use to manage billing, made some major changes to their model and it pissed a lot of people off. To me, the problem was in communication.

I don't mean communication when they made the change, but communication early on, before the change.

People have to understand that you're in this to make a living, or at least be sustainable. Communicate that to them before you implement the structure change. Make sure they always know that eventually you will move to a freemium model, especially if you will restrict the free users once the premium version is available.

Chargify should have been more open from the get-go, and communicated that as they started realizing that their business model wasn't having high enough conversions.

Don't follow their lead. Remember, you can always grandfather-in old customers.

If you're simply planning on adding content/features for premium users and otherwise keeping the app the same for standard users, you have no need to worry at all. People who love your product will upgrade for the features if they are worth paying for, and the others will simply be content with their bare-bones version.

The general mobile app customer is very much used to this type of free/lite to premium offering. As long as you a clear with the customer to what is included in the free version they will have no complaints.