While T-Mobile and AT&T have been battling it out over social media and in stores, to the benefit of their customers, AT&T has now lost a court battle to the fourth largest carrier in the US. John Legere, T-Mobile’s CEO, must be grinning from ear to ear over the recent court ruling, not just because it’s a win over AT&T but because it’s protecting T-Mobile’s beloved magenta coloring.

Hothardware.com reported on Monday that a Federal court has ruled that AT&T has infringed on T-Mobile’s trademarked magenta coloring scheme.

AT&T’s newly rebranded AIO prepaid carrier has been using a color they call “plum” which looks an awful lot like T-Mobile’s magenta, and a federal court judge has agreed. They’ve told AT&T and AIO, to “stop using magenta or similar colors in all of it’s marketing and advertising, including stores, websites and social media.” T-Mobile said in a statement.

AIO Wireless is AT&T’s prepaid subsidiary that will merge with Cricket Wireless when AT&T’s merger with Leap Wireless is completed later this year.

While T-Mobile has been building up their reputation of being the “un-carrier”, AT&T has rolled out AIO wireless as a no contract, simply priced, relatively inexpensive alternative to their traditional offerings. They offer a basic plan with 500mb of data for $40 a month, 2.5gb for $50 a month and 5gb of data for $60 a month. It appears that Cricket’s unlimited data plans may end up a thing of the past when they are rolled into AIO wireless.

In the meantime, AIO needs to go back to the drawing board for a new color scheme.