Can you update an iPhone without updating apps?

I want to update my iPhone 4 to iOS 6 but the garage band app needs an update and with the new update it says it will require iPhone 4s or later to run it. I spent $5 on it and I use it a lot so I don't want to lose it but I also want to update the software on my phone.

If it says it requires an iPhone 4s to run then do not update the application. But you can update to iOS 6 without any problems. Just make sure you do NOT update the GarageBand app.