I received an email from CoffeeCup about the new RED V4 and in that email it states,

Pay Once — Use Forever!
With V4, you can enjoy a perpetual usage license. That's right, pay once and enjoy the app forever. If you cancel the subscription (which includes free upgrades and image hosting), you can still continue using the app without any limitations on the number of sends and exports. How cool is that!?

I am not understanding, It says you can pay once and use forever then it say's "if you cancel the subscription (which includes free upgrades and image hosting), you can still continue using the app without limitations.

If RED V4 has switched to Pay once - Use Forever! What subscription is being referred to?

Perhaps someone from CoffeeCup could provide some clarification on how on this? The reason I stopped using RED V1 was that the promises of Pay Once were made and out of nowhere, a whole new version was released that required purchasing a whole new version to get the new features. RED 4 looks great, however, I have my doubts about taking another chance with it. So if CoffeeCup could provide a clearer understanding of the new Pay Once - Use Forever! claim, that would be great.

I'm not from Coffeecup, but...
It's actually quite simple. You pay once for Site Designer 4.0.xxx ('xxx' represents a build number), and it's yours for ever. Included in that payment is one year of free updates, say build 'xx1', 'xx2', in other word all the updates that happen within a year from your purchase. When the year has passed, you can still use every bit of the app, but if there is another update (and there surely will be!) after a year + one day, you need to extend your subscription if you want that update.

The updates may include fixes, new features, adaptions if necessary for being used with whichever Mac or Windows OS being the current one etc. When there is an update, there usually is a change log posted in the forum, so that you can see what you will be missing out on, if you decide not to continue the subscription.

So, clear as mud?

Here's how I understand it.

The subscription for RED includes:
- Ability to export your email code. In previous versions, there was some type of limitation on this if you did not have a subscription. Now, if you purchase the software, you will be able to always export your code.
- RED has the ability to send email through your email account. In previous versions, there was some type of limitation on this if you did not have a subscription. Now, if you purchase the software, you will be able to always to send.

The subscription also includes web site hosting. If you send an email that has image(s), the image(s) have to be stored on a web server. Because the subscription includes Coffeecup web hosting, your email images are automatically stored in your Coffeecup web hosting account. Nothing extra is needed.

If you cancel your RED subscription, you will still be able to send and export, but you will not have Coffeecup web hosting built in so you will have to put your images on another web host.

Just as a side note, if you subscribe to Coffeecup's Shopkeeper or Total Pro Plans and pay annually, you also get Site Designer for free.