Even though the iPhone 4S looks essentially the same as the current iPhone 4 model doesn’t mean current accessories and cases will work with Apple’s newest handset. In other words, you might actually have to buy a new case come Friday when the iPhone 4S arrives, according to iDownloadBlog.

In February, Apple unveiled the Verizon iPhone 4. At the time, the company also made a slight change to its Bumper line of cases. The reason? The Verizon iPhone’s placement of the hold button, as well as the two volume controls is slightly different than those on the AT&T iPhone 4 model. Now, the Verizon design has been carried over to the iPhone 4S, no matter the carrier.

Therefore, while existing Verizon iPhone customers will have no problem using their existing cases with an iPhone 4S, AT&T customers may not have the same luck.

The iPhones Aren't All The Same

According to the report:

As the image above shows, the iPhone 4S is actually the same as the CDMA iPhone 4, which isn’t quite the same as the GSM release of the world’s best-selling smartphone. Notice the ever-so-slightly different placement of all three controls on the side. What this means is that some cases may not fit the new handset. We suspect that all cases made since the CDMA iPhone 4 was released earlier this year will fit fine, due to being made with wider gaps for the buttons.

Our advice: Don’t preorder a case for your iPhone 4S unless it is clearly marked as being compatible for both the iPhone 4S and iPhone 4. Better yet, wait until you have your new handset and see if it works with your old case. If it doesn’t, go shopping for a new case.

We’ll let you know more about this once we finally get our hands on an iPhone 4S this Friday.