Couple of our readers saying us that they are receiving notice from AT&T on tethering data plans. The users of MyWi the popular jailbreak app that allows you to tether your data plan, receiving warning text messages and emails from AT&T to update their data plan to the official tethering plan.

AT&T sends the text messages on which they are telling about their official tethering plan. Also AT&T sends email to MyWi users to update their data plans to unlimited 4 Gb plan before 27 March, on which officially they have option for data tethering, if they didn’t update their plans and still tethering data plans than their data plan automatically changes to 4GB.

Dear [Customer],

We’ve noticed your service plan may need updating.

Many AT&T customers use their smartphones as a broadband connection for other devices, like laptops, netbooks or other smartphones– a practice commonly known as tethering. Tethering can be an efficient way for our customers to enjoy the benefits of AT&T’s mobile broadband network and use more than one device to stay in touch with important people and information. To take advantage of this feature, we require that in addition to a data plan, you also have a tethering plan.

Our records show that you use this capability, but are not subscribed to our tethering plan.

If you would like to continue tethering, please log into your account online at Cell Phones and Cell Phone Plans – Wireless from AT&T, or call us at 1-888-860-6789 Monday – Friday, 7 a.m. – 9 p.m. CST or Saturday, 8 a.m. – 7 p.m. CST, by March 27, 2011 to sign up for DataPro 4GB for Smartphone Tethering. Here are details on the plan:

DataPro 4GB for Smartphone Tethering
• $45 per month
(this gives you 4GB in total, combining both your smartphone data plan for $25 and the tethering feature, $20)
• $10 per each additional GB thereafter, added automatically as needed
• Mobile Hotspot capabilities are included for compatible Smartphones

If we don’t hear from you, we’ll plan to automatically enroll you into DataPro 4GB afterMarch 27, 2011. The new plan – whether you sign up on your own or we automatically enroll you – will replace your current smartphone data plan, including if you are on an unlimited data plan.

If you discontinue tethering, no changes to your current plan will be required.

It’s easy to track your usage throughout the month so there are no bill surprises. For example, we send you free text messages when you reach 65, 90, and 100 percent of your plan’s threshold. If you would like to monitor your account more closely, go towww.att.com/dataplans to learn about other ways to track your data usage.

As a reminder, our smartphone data plans also include unlimited usage of Wi-Fi at no additional charge. AT&T smartphone customers can use Wi-Fi at home or on-the-go at any one of our more than 23,000 U.S. hotspots already included in your data plan.

Thank you for bringing your account up to date. We appreciate the opportunity to continue to serve your mobile broadband needs.

Sincerely,

AT&T

According to the users, it seems that this messages is only sent to those users who were currently on Unlimited Data package. This time its not clear how AT&T detects that users are tethering their phones.