Welcome to Law.com Class Actions: Critical Mass, Law.com’s weekly briefing for class action and mass tort attorneys. I’m Amanda Bronstad. Class actions are piling up against T-Mobile over a massive data breach announced this month. A hearing today in a high-stakes opioid trial in New York focuses on whether to issue a civil contempt order against defendant Endo and two of its law firms. Find out who got appointed to lead opioid lawsuits against Purdue Pharma consulting firm McKinsey & Co.