Are you having a bit of buyers remorse because you bought that iPhone 4 a few months ago? Well luckily if you follow our guide you can most likely upgrade to the iPhone 4S for a decent price if you plan on paying the no-commitment pricing, but we just found a catch.

We called up AT&T customer support to see if iPhone 4 owners who bought early would be eligible for the subsidized iPhone 4S pricing even though it hasn’t been 18 months. In previous years they have allowed this (although they would often just sneak up your eligibility date without telling you). Unfortunately, the rep had not heard of that happening and in a follow up email we received some information:

If you are interested in purchasing an iPhone at no-commitment Pricing the following restrictions apply:

• Only available to existing AT&T customers with an active account.
• All sales at the no-commitment price point must be associated with a mobile number.
• The no-commitment price is limited to one iPhone per mobile number for the lifetime of the mobile number.

So it seems if you’ve ever bought an iPhone at the no-committment price, you have to wait it out until your are eligible, or switch carriers.

Keep that in mind when pre-order time comes on the October 7.

The iPhone 4S will be released October 14.