Google's Wear OS 5.1 reportedly runs an entirely new version of Android

What you need to know

• Google has reportedly started testing a Wear OS 5.1 update on the Pixel Watch 2 based on Android 15.
• A rumored insider stated that the build ID numbers for the software changed from "AW2A" to "AP4A," strengthening the theory.
• Google has seemingly committed to annual Wear OS update cycles as the company launched OS 4 in 2023 and has brought OS 5 this year.

Google was spotted testing a new build of Wear OS that supposedly runs off the next major Android version.

The existence of a test build was reported to Android Authority by a rumored "insider," stating Google has started developing a Wear OS 5.1 update. It was stated that the new build swapped out its initial lettering, opting for "AP4A" instead of Wear OS 5's "AW2A" number.

This new Wear OS 5.1 build is reportedly based on Android 15, a theory seemingly bolstered by the shift in build ID number. Wear OS 5, by comparison, is still on Android 14.

More importantly, the unknown insider said that Google was testing the upcoming software on the Pixel Watch 2 internally. The company's Wear OS software has always lagged behind the current Android software — and was never so consistent. Wear OS 4 debuted in August 2023 and with Wear OS 5 arriving first on the Galaxy Watch 7, it seems that Google hit its stride .

With that in mind, there's uncertainty about whether or not Google will keep the update as "Wear OS 5.1" or if it's just testing Wear OS 6 early. Mishaal Rahman writing for the publication states that the specifics of the 5.1 update are unknown. However, if Google were to update its "APIs or app-facing system behaviors," that could warrant a major number increase.

We've got a toss-up regarding when Google could launch the Pixel Watch 3 as it has yet to tease it. The company is gearing up for an earlier hardware event on August 13 , so we'll see when the device will launch. Google's Pixel Watch 3 is expected to arrive sporting Wear OS 5, which was said to come "later this year" during its developer preview in May.

While we await the "stock" version of Wear OS 5, Google previously clued us into a few of its key upgrades . When running default settings, Google stated the software will utilize 20% less power when compared to last year's version.

Additionally, Android Health will deliver improved running data and goals alongside Health Connect upgrades. Another critical aspect of the base Wear OS 5 software is that it runs off last year's Android 14. With Google seemingly more committed to annual Wear OS release cycles , perhaps this 5.1 update is a testament to that. We're still waiting for the stable launch of Android 15, so maybe the company's looking to sync up these launches.