Unable to update to ios 13 or 14

The Apple support agent you were speaking to should be reprimanded for not knowing a 6s plus is supported. They have this information right in front of them. I have iOS 14 on my 6s right now.

With 14 released, you cannot get 13 anymore. Some things that may be preventing you from upgrading:

1. The phone has less than 50% battery power remaining. Plug it in.
2. You don't have enough free space to download the upgrade data.
3. You have enough space to download the upgrade data, but not enough remaining free space to install it.

What do you see on your screen when you attempt to update your iPhone to iOS 13/14?

Furthermore, can you double check something? Open Settings ➔ General ➔ About ➔ Model Name : What does it state here?

Axel F.

The IMEI doesn't tell anyone anything about a phone's make or model. It's an identifier for a cellular carrier.

Assuming you followed Alex's menu steps and it said 6 and not 6s, then a 6 is what you have.

What is the model number on the back of the phone? Nothing to worry about posting that info. All that will tell anyone is what model phone you have.

That would make it a 6 plus, not a 6s plus.

Then that's why. A 6 is not a 6s. It's one step under the cutoff. Doesn't sound like much, but there's quite a bit of a hardware difference between the 6 and the 6s.

You're welcome. 🙂