The holiday season means buying gifts for those you love. For the mobile smartphone users on your list, this might mean giving them an iPhone. As you enter your local Apple Store, you are amazed by the iPhone 4, but you’re not too happy with the price points ($199 or $299). Instead you buy the iPhone 3GS, which fits into your budget at $99.

Perhaps you made the wrong choice.

When the iPhone 4 debuted last June, Apple kept its older model, the iPhone 3GS on the market too. Despite being nearly 18 months old, the iPhone 3GS is new to those purchasing the device today. With the introduction of the iOS 4.2 update, Apple is already telling 3GS users their device is outdated, or will be soon.

While most of the features available in iOS 4.2 are fully compatible with the 3GS, one is not. The free Find My iPhone feature is available for the iPhone 4, iPad and fourth generation iPod touch. But, not the iPhone 3GS.

Knowing Apple, this is just one of many upcoming features that won’t work on the iPhone 3GS. Come the next iOS update, additional features will not run on the 3GS. Just ask any iPhone 3G user how they like the latest iOS update; they don’t.

I understand technology is always changing. However, existing Apple products should work with current software updates. If not, Apple should no longer sell the product.

What are your thoughts? Leave your comments below.