The Galaxy Watch 7 and the Watch Ultra were launched earlier this week with upgraded internals and a new BioActive Sensor. While the improved sensor is claimed to be more efficient than before, it forced Samsung to remove a key feature previously unique to the Galaxy Watch lineup.

Older Samsung Galaxy Watch models — including the Galaxy Watch 6 — could be charged when placed on the back of a Samsung phone that supports wireless charging. This functionality relies on “Wireless power sharing,” commonly known as reverse wireless charging, which allows Samsung phones to add battery life to accessories such as earbuds and select Galaxy Watches through wireless charging.

Several past generations of Samsung flagships, including the newly announced Galaxy Z Flip 6 and Fold 6, have supported reverse charging. The maximum output is limited to only 4.5 watts, and as you would expect, it is intended to be a fallback option when you can’t access a proper power supply through a wall adapter or a power bank.

However, with the new Galaxy Watch 7 and Watch Ultra, Samsung had to change the shape of the back glass to accommodate the more advanced BioActive Sensor. A new support page that cropped up after the recent Unpacked event states that the design change resulted in increased distance between the back of the new watches and the wireless charging coil that’s inside them. As a result of the increased distance, the wireless power-sharing feature would no longer be supported on the Galaxy Watch 7 and the Watch Ultra. “We appreciate your understanding,” Samsung said.

The ability to charge your Galaxy Watch by placing it on the back of your phone has never truly been on par with the puck-shaped wireless charger that comes in the box. However, it can be a lifesaver if your Galaxy Watch is running low on juice and you aren’t near an outlet. More importantly, Samsung — until now — was the only manufacturer to offer a feature like this on its smartwatches.

The implementation hasn’t been perfect, though, and is loaded with caveats. First, because it only works with Samsung phones, and not just any other phone with reverse wireless charging. It requires very specific Samsung Wireless Fast Certification on the device or the charger for it to function. Secondly, the curved strap lugs introduced with Galaxy Watch 5 make it incredibly difficult for the watch to sit on a broad, flat surface, like the back of a Samsung phone or a wide wireless charger. So, the removal of the feature appears to be destined for a few generations, with Samsung slowly easing us away from it instead of removing it suddenly.

In addition to removing support for reverse wireless charging, Samsung also warns against slower charging on the Galaxy Watch 7 and Ultra if you use older chargers. Instead, it recommends you use a newer model — EP-OL300 — that likely supports faster charging and is bundled with the new watches.