Recently, Apple has been releasing updates for the iPhone 4S so they can squash all the bugs it may have. Turns out the iPhone 4S had a battery life bug, but Apple fixed it by releasing iOS 5.0.1 within just weeks of releasing the new iPhone. You know, we iOS owners get constant updates unlike *cough* Android owners. Surprisingly, yesterday Apple released a tweaked version of iOS 5.0.1 (build 9A406), but the purpose of the update was unknown and  was not being made to all users. The update was only made available to those newly updating to iOS 5.0.1.

Today, a new Apple support document suggests that the tweaked update may have been designed to deal with  some users experiencing with SIM card-related errors.  According to the support document, the “iPhone 4S may have difficulty recognizing a micro-SIM card,” and will subsequently display “Invalid SIM” and “No SIM Card installed” alerts or “No Service” and “Searching” status bar messages. Since the update may only affect a small portion of users, Apple may have chosen not to make the update available to all users.

According to Apple, if you are encountering these issues, download and install the latest build of iOS 5 by restoring the unit through iTunes, and confirm that the software version reads “5.0.1 (9A406).