T-Mobile is set to become Microsoft's second European customer for mobile phone software, following Orange.
Handsets are expected to be available in the summer, and the German operator will buy the devices direct from Taiwan's High Tech Computer, as did Orange.
T-Mobile confirmed that it will add its own services to the device, which will have all standard Microsoft features such as email, messaging, picture taking and a calendar.
Orange has sold around 40,000 of its Microsoft-based phones since the launch late last year.
Cotton seedling freezes to death as Chang'e-4 shuts down for the Moon's 14-day lunar night
Fortnite easily out-earns PUBG, Assassin's Creed Odyssey and Red Dead Redemption 2 in 2018
Meteor showers as a service will be visible for about 100 kilometres in all directions
Saturn's rings only formed in the past 100 million years, suggests analysis of Cassini space probe data
New findings contradict conventional belief that Saturn's rings were formed along with the planet about 4.5 billion years ago