Citizen is preparing a major change for owners of certain Bluetooth-enabled watches: the company will end support for several companion smartphone apps on December 31, 2027. If you use a Citizen watch that relies on its app for connected features, it’s worth checking your model now so you know what to expect over the next couple of years.
According to the notice dated March 30–31, 2026, the decision affects watches built on the W770, W770 Riiiver, W410, and W510 calibers. These calibers power a broad lineup of Citizen Bluetooth watches, including models tied to the Riiiver ecosystem. For many owners, the companion app is what unlocks the “smart” side of the watch, such as phone notifications, automatic time synchronization, and other app-based functions that go beyond standard quartz timekeeping.
Once the deadline hits at the end of 2027, those app-linked features will no longer be supported for affected models. Citizen also cautions that starting January 1, 2028, the apps may stop working correctly or consistently as iOS and Android continue to evolve. In other words, even if the app still opens on your phone, future operating system updates could cause pairing issues, syncing failures, or missing features—and Citizen is making it clear it won’t be responsible for functionality that’s lost after that point.
Citizen has also published a long list of impacted references. While the full list is extensive, it includes multiple watches with case numbers that begin with “EE” and “BZ,” covering several generations of its Bluetooth-equipped lineup.
The good news is that these watches won’t suddenly become unusable. Citizen says core timekeeping will continue to be supported as long as repair parts remain available. Practically speaking, the watch should keep operating as a normal quartz timepiece even after connected features fade away. The bigger change is that the Bluetooth experience—anything dependent on the phone app—will become less reliable and eventually irrelevant once official support ends.
This move highlights a common reality with hybrid and early smart-connected watches: even when the hardware still works, software and mobile operating systems don’t stand still. Over time, maintaining older app platforms becomes increasingly difficult, and features that once made a watch feel “smart” can disappear when app support winds down.
If you own a Citizen Bluetooth watch and regularly use app features like notifications and automatic syncing, the most important step now is to confirm whether your watch uses the W770, W770 Riiiver, W410, or W510 caliber (and whether your case number falls into the “EE” or “BZ” ranges). That will give you a clear idea of whether you’ll be affected by the December 31, 2027 cutoff—and how much you rely on the connected functions today.
