New phone codenamed "Shamu" will feature a 5.9-inch screen, sources tell the Wall Street Journal.
Having filed for bankruptcy earlier this year, ongoing troubles at Pantech have forced the company to seek a full buyout.
The company brings the entry-level handsets in Brazil, followed by other countries elsewhere around the world in the coming weeks.
With the Liberto 820, Doro is hoping its simplistic approach to Android will help make smartphones more appealing to older users.
Sporting a Snapdragon 800 quad-core processor and 13-megapixel lens, the 5-inch PadFone X smartphone can dock directly into a tablet for a more immersive experience.
Micromax, a five-year-old Indian company, now leads the handset market in that country, but it's not all bad news for Samsung there.
Despite reluctance from three major carriers, creditors have agreed to extend Pantech's deadline for debt repayment by two years, keeping the South Korean company alive for the time being.
The third largest phone maker in Korea continues to post losses while still owing debt to various entities, including Korea's three carriers.
Motorola will hold a London press event on May 13 to introduce its newest smartphone.
Optus cuts handset subsidies and pushes up the price of mobiles, arguing similar moves from Telstra and Vodafone allow it to remain competitive.