Sprint Nextel today announced that it is still planning to shut down the Nextel National Network by the end of June.

The company has stated that June 29 will be the final day of full Nextel iDEN network service. On Sunday, June 30, iDEN phones will not receive voice or data. Sprint stated the equipment that powers the network will be switched off that day “in rapid succession.” The Nextel push-to-talk service will be converted to Sprint’s CDMA network.

By the time the shutdown comes, Nextel customers will have had just over one year to prepare for it. In addition to the letters and emails Sprint has already sent throughout the year, the company will also be sending text messages and using “other communications tactics” in the days leading up to the shutdown.

“Our shutdown communications are meant to give customers more than enough lead time to plan their migration,” said Bob Azzi, SVP of the network division at Sprint. “This has been especially important for public safety, first responders, health care users and others who rely on the service to protect and preserve people’s lives. We strongly urge customers to migrate now, rather than wait until the last minute.”

Sprint has been losing large numbers of subscribers who are leaving the Nextel platform. The wireless carrier is currently in talks for a $20 billion merger with SoftBank, though it is also entertaining a $25 billion offer from Dish Network.