To check your iPhone upgrade status, you can contact your wireless carrier or check with Apple. AT&T customers can dial *639#, while Verizon customers can dial #874. Sprint or T-Mobile customers can log in to their account to check their status. It's important to note that these methods may vary depending on your specific carrier. Checking your upgrade status allows you to determine if you are eligible for a new iPhone or if you need to wait for an upgrade.