Over the weekend, a rumor spurt up claiming that OnePlus will unify its Oxygen OS and Hydrogen OS, and call it H₂OOS. Hydrogen OS or H2OS was the company's Android-based Google-free operating system that it used to ship in OnePlus phones in China until it started to ship ColorOS after OPPO and OnePlus merger. Popular leaker Mukul Sharma posted a picture of OnePlus' H₂OOS logo trademark on Twitter starting the discussion that if the upcoming unified version of ColorOS, OxygenOS, and Hydrogen OS software will be called H₂OOS.
However, it doesn't seem to be the case. As a number of reports note, OnePlus first filed the trademark for H₂OOS seven years ago in China back in 2015. For reference, that's the time the OnePlus 2 was introduced. But, it's highly unlikely that the company would revive the branding seven years after filing the trademark. The company has since then filed a new filing for the same term, as per AndroidPolice, but it's been kept confidential.
It's highly unlikely that OnePlus would revive the H2OOS branding. As Android Authority notes, it's "far more likely that it flirted with the idea of branding Hydrogen OS as H2OS or H2OOS," but there's no evidence to support this speculation. To prevent others from using a similar name, OnePlus could have filed a trademark for both H2OS and H2OOS in 2015, just in case it plans to use one in the future.
And now, the idea of OnePlus opting for H2OOS branding for its unified Oxygen OS and ColorOS name is looking far-fetched. We should find out the name of that operating system very soon, alongside the global launch of the OnePlus 10 Pro, but there's no official word on the launch of the OnePlus 10 Pro in global markets just yet. Previous rumors have suggested that it will make it to the international borders in the next few months, but nothing has been confirmed as of now.