Credit: Edgar Cervantes / Android AuthorityTL;DRAT&T is increasing legacy plans by $10 a month for single-line users, or a flat $20 increase for any number of lines on a family plan.In addition, it seems AT&T has now lowered its special discounts for teachers and medical professionals to a max of 20%, down from 25%.The discount changes affect new and legacy plans immediately, though the price increase isn’t expected until sometime in April.Last week, AT&T announced new core plans that are largely a sidegrade at best and arguably are more of a downgrade in many ways. At the time, we ran a poll, and most agreed that AT&T customers were better off sticking to a legacy plan.It seems AT&T predicted that many customers would feel this way, as the company has announced it will raise prices on legacy plans starting in April. It’s almost like they are trying to make their existing plans worse, so customers switch without giving it much thought.