How do I upgrade an IP phone's software (ITP-5021D). I see I can use TFTP but where do I get the software or what TFTP site can be used?

The software and proceedure are on the Samsung website. You need to be a dealer to get access.

I am not a dealer.... How am I supposed to upgrade this phone?

That model phone is still new and the system might still be under warranty, contact the installing company. If you can't locate the installing company, then use the PM feature to contact a moderator or an administrator of this forum for assistance.

Just looked on the Samsung site and I cannot find any support related to this. Will someone give me a number or website for help. The installing company is unresponsive.

Send me a PM with the zip code of the customer and we will get you a list of Samsung dealers.
What you are looking for requires certification from Samsung. The website with this software is for dealers only. You could mess up the phone and the customer will loose the warranty. If a new Samsung dealer is involved the warranty will transfer.

You should also complete your profile, we do not know where you are located.