Suitcase maker Away sent some customers an email this week letting them know that customers who fly Delta must remove the battery from their suitcase before they board, even if they’re not checking the bag. Away sells a bag with a built-in battery for charging your smartphone or other devices. Other “smart” bag manufacturers sell bags in which a battery is also used to power locks and GPS tracking. The airline considers the batteries in such suitcases to be a fire hazard.

Away’s email suggests that it’s a change from Delta’s previous policy, but a Delta representative tells Fortune that it is simply a clarification of the existing policy. The policy, which carries a timestamp suggesting that it was changed on Jan. 13, currently reads:

Effective Jan 15, 2018, Delta will not accept smart bags with non-removable lithium-ion batteries as carry-on or checked baggage on any Delta mainline or Delta Connection flight.

Customers checking a smart bag with a removable lithium-ion battery must remove it and take it with them into the cabin. Customers carrying-on a smart bag containing a removable lithium-ion battery must remove it from the designed enclosure prior to boarding the aircraft. Once the battery is removed from the bag’s designed enclosure, the battery may be placed inside the carry-on bag. The removable battery does not need to be carried separately from the smart baggage.

Delta is one of a number of airlines to crack down on smart luggage and luggage with built-in batteries this year. American Airlines, Delta, Southwest, United, JetBlue, Air Canada, LATAM, Lufthansa, British Airways, KLM, and Air France require passengers to remove the battery from smart bags before checking them. Delta is currently the only airline that requires the batteries to be removed when they’re brought aboard as carry-on luggage as well.