Carrara 8.5 beta is out and  has a an accompanying serial number that expires.  If we bought Carrara 8, shouldn't each update 8.X to 8.X up to version 9.0 be free and accessable indefinately?  Could someone please explain why an expiration date on each beta or is the expiration only for those who did not purchase Carrara 8?

Personally I don't download nor install Betas. The term 'BETA' in itself means it is only temporary and will be replaced by the permanent version at a later date. But I most admit I have not heard of a BETA with a Temporary Serial Number.

Because they are time limited Beta's that when it expires, the new beta should be out.  Eventually it will be out of beta and the full 8.5 available for purchase.

I have had a number of Beta from different venders do this.  Its to give people a taste of what changes are coming and allow additional eyes to do things with the product and get feed back.

If the Beta never expired then people wouldn't purchase either.

The expiration had other thing too: its like a timeline, and tells when a new beta will be out or when is supose to have the final version too.

The expiration also ensures that everyone is using the latest beta and that the dev team is getting bug reports based on the latest build, not a earlier version. This way they aren't chasing their tails trying to fix things that are no longer a problem, or that show up under different circumstances in the newer build.