The Kansas Department of Revenue this week sent a letter to Kansans affected by a new law, which took effect Thursday, that requires the gender marker on a driver’s license to match a person’s sex at birth.

The letter informs trans Kansans that because the Legislature didn’t include a grace period for updating credentials, they are “invalid immediately, and you may be subject to additional penalties if you are operating a vehicle without a valid credential.” A spokesman for the agency told Kansas Reflector the law invalidated about 1,700 licenses.