Carrier ATT: Your new device requires a new SIM card

[L-Tuned]

I just got a free text message from AT&T saying "Your new device requires a new SIM card to give you access to all services. Please visit your local ATT store to get a new SIM. Thanks."

I am currently using the old SIM card from my iPhone 5 on my 6+ and it has been working without any issue. Do I really have to get an new SIM card? I'd like to avoid going to a AT&T store if possible Anyone else receive this? Thanks.

 

[AllergyDoc]

You need the new sim card to utilize new features like Apple Pay.

 

[iceperson]

You need the new sim card to utilize new features like Apple Pay.

^^

I believe you need a 27 or 28 series SIM for full functionality on an iPhone 6.

 

[KBianc14]

New SIM Needed Message on hundreds of company AT&T iPad Air

The company I work for deployed 900+ iPad Airs to our sales reps, and I manage the company-paid data for all 900+ lines. I recently was looking through some of the lines, and noticed that the majority of the lines showed a "Device ####### needs a new SIM to access all of its features" message on 10/9.
I worked with our AT&T contact, and they told me "As these are iPad Air LTE devices the user may have an old 3G SIM card" which does not sound accurate to me. The majority of the users were on iOS 7.1.2, since we have a custom company-app that was not compatible with iOS 8 at the time. So did they really push the “new SIM needed” message only to utilize new features like Apple Pay? I had lots of users reporting Cellular Data connectivity issues around 10/9, so want to be safe (but definitely don’t want to coordinate swapping out hundreds of SIM cards across the country).
It’s possible that our MDM (Citrix Xen Mobile / Citrix Worx), or our custom app is interfering with connectivity. Any additional information would be very helpful!!