A tipster has just sent along a photo that indicates AT&T may soon be offering a 5GB data plan to its smartphone users. The alleged DataPro 5GB Plan, which includes tethering and mobile hotspot usage, would be priced at $50 — $5 cheaper than what's currently available when you factor in a $10 overage charge on top of the 4GB DataPro package. Though our source tells us the plan appears on a poster exclusively with LTE devices, there's no mention in the text that it's restricted to them, unlike Verizon's double data promotion which is technically a better deal but applies to LTE alone.

On reaching out to an AT&T spokesperson to confirm availability of the plan, the reply was very clear:

This is an error. There are no changes to our data plans.

That said, the circumstances of this tip are interesting. Our tipster — who works at an AT&T corporate store — says that the poster arrived at the same time as an identical poster with the current $45 4GB plan in place of the $50 5GB one; only the $45 poster was identified "for immediate use." As AT&T says, it could truly be nothing more than a mistake — the company already offers a $50 5GB plan for data devices like the Elevate 4G, and there could've been some confusion somewhere between design and printing. At any rate, Verizon's aggressive LTE promo puts some price pressure in this segment of the market, and AT&T has yet to respond; for two competitors that have a historical tendency to stay in pricing lockstep, that's not likely to stay true for long.

Chris Ziegler contributed to this story.