https://www.cnet.com/news/millions-of-myfitnesspal-accounts-hacked-under-armour-says/

Under Armour on Thursday said an "unauthorized party" had grabbed information including usernames, email addresses and hashed passwords, from about 150 million MyFitnessPal accounts. Hashed passwords have been converted to a string of numbers and letters that can't be reversed. 

The company said it began sending emails and in-app messages to the mobile app's users on Thursday, four days after discovering the breach, which occurred in late February.