Log in to your at&t wireless account and see if you are eligible for an upgrade. If you are eligible and want a new phone with carrier subsidy then yes you will need to sign up for another two years. You can also do this with many third party vendors such as Let's talk although their upgrade options are often limited by the carriers to specific plans.
If you are no longer with the employer then you are not entitled to special deals and rates, as these are perks of employment. However, some companies do have special deals for retired members of the company. It is best to call at&t customer service with this rate question as it can vary from case to case.
I plan to upgrade my phone, but the full two-year contract is not up yet. If I want to upgrade my phone now and renew my contract, do I have to do that with AT&T directly, or can I go through some third party? And can I do a two-year renewal now, or do I have to wait for the current contract to end?
If so, where should I go to get the best deal? I'm not looking for a new rate plan, since I'm just going to renew my contract. I've heard of letstalk.com, are there any others?
One other thing -- my original contract and rate plan included a deal from my employer. If I renew through some third party like letstalk.com, will I still retain the great rate plan I have? I don't totally understand how that works.