BlackBerry announced on Tuesday it will end its licensing agreement with T-Mobile when it expires on April 25th, meaning the fourth-largest carrier in the United States will soon no longer be able to sell BlackBerry products. In a press release, John Chen, BlackBerry’s CEO, said although the two companies had “a positive relationship for many years,” their strategies were “regretfully, at this time … not complementary.” The move comes after a lengthy spat between the two companies. In February, T-Mobile sent out promotional material to customers that offered discounts on the iPhone when upgrading from BlackBerry devices. Chen responded with a blog post, in which he said he was “outraged” by the “inappropriate and ill-conceived marketing promotion.” T-Mobile responded by offering $250 to customers wanting to upgrade from an older model to a newer BlackBerry.