T-Mobile (NYSE:TMUS) said it will unveil its next uncarrier move this Monday, and it's inviting customers to tune in.

CEO John Legere tweeted an invitation to the event this morning, saying the operator will livestream it "pretty much everywhere" starting at 1 p.m. ET. T-Mobile also posted a countdown page for the event. T-Mobile's invitation to its latest uncarrier event features a volume dial positioned at 11, a possible indication that the event might be focused on music.

The company has launched 10 uncarrier promotions since March 2013, with varying degrees of success. Its initial effort, which ended two-year contracts in favor of equipment installment plans (EIPs), changed the mobile landscape in the U.S., forcing other major operators to follow suit. Similarly, in January 2014 it began offering to pay off the early termination fees of users under contract to switch to T-Mobile, an offering that proved remarkably successful if costly in the short term.

And Binge On, which was introduced during its Uncarrier X event in November, has proven popular with customers, enabling them to watch zero-rated video even as it eases congestion on T-Mobile's network.

Other offerings have been less disruptive. T-Mobile's Test Drive, which launched in June 2014, was phased out a year later with the rollout of a 30-day guarantee exclusively for customers using Jump! On Demand, a device-upgrade program.

T-Mobile executives have been teasing uncarrier 11 for weeks, although no details have been disclosed. A report last month, however, indicated the operator will launch a branded app that enables customers to win prizes from partners including Wendy's and Vudu as well as equity in the carrier.

Coincidentally, AT&T today announced a new rewards program slated to launch this summer. "AT&T thanks," as it will be branded, promises to reward customers with movie tickets, advance access to concert tickets and other goodies.

For more:

- see T-Mobile's countdown page

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