Sprint said the push-to-talk service that is replacing its outgoing iDEN network now has more than 1 million customers.

The Tuesday announcement came just hours after AT&T said it planned to launch its upgraded PTT service in November, a product aimed squarely at attracting Sprint customers migrating off iDEN.

Sprint has been losing iDEN customers to other operators for years. It is working to improve the retention of iDEN customers with its Direct Connect CDMA-based PTT service, which launched last October on the Kyocera DuraMax.

Chief sales officer Paget Alves said that the customer milestone was an "important achievement" for Sprint.

The company did not specify how many of its current Direct Connect customers were new to Sprint, versus subscribers brought over from iDEN. The carrier had 4.4 million customers on its iDEN platform at the end of June.

Direct Connect faces competition from Verizon’s walkie-talkie-style service, as well as AT&T’s pending launch of its “enhanced” PTT offering. AT&T is marketing its new product directly to Sprint iDEN subscribers.

CEO Dan Hesse said during the company's most recent call that the company only retained about a quarter of its outgoing iDEN customers during an average year but managed to recapture 60 percent of the customers leaving iDEN during the second quarter and 46 percent during the first quarter.

Its iDEN network is slated to be decommissioned as early as June 30, 2013. Sales of most iDEN devices have been discontinued, and Sprint is working to move the customers still using the phones to its new service.

About 9,600 iDEN cell sites were taken down by the middle of the year. The replacement PTT service has a broader footprint than iDEN, more than doubling coverage to 2.7 million square miles, including the addition of 2G and roaming service.

Sprint plans to use the 800 MHz spectrum left over from iDEN to supplement its LTE network on the 1900 MHz band. The PTT overhaul is part of Sprint's broader network upgrade project, which has it ripping out old base stations and replacing them with new equipment that supports LTE. Hesse said in June that the company's vendors were on track to have 12,000 of the new sites on-air by year-end.