AirPods Max are due for an upgrade, and Apple could be planning a refresh for its $549 over-ear headphones if current shipping dates and low retail stock availability are an indication.

Recently pointed out by @AppleTrack on Twitter, current shipping estimates for AirPods Max in all colors on Apple’s US online store have slipped to mid-April, with in-store pickup unavailable in many locations. Over at Amazon, customers ordering Apple’s over-ear headphones should see shipping dates between mid-April and late May depending on their color of choice.

All other AirPods models remain in healthy stock with immediate delivery and same day in-store pickup across majority of Apple Store locations.

Announced on December 8, 2020, AirPods Max represents Apple’s first entry into the over-ear headphones market. The headphones feature the H1 chip, Active Noise Cancellation, Adaptive EQ, and 20-hour battery life. It is unclear what updates the new AirPods Max would offer, save for a refreshed palette of new colors. Perhaps Apple would include its new H2 chip in the headphones, bringing it closer in line with its second-generation AirPods Pro.