OnePlus has announced that they will be merging The Oxygen OS and China-Only Hydrogen OS for Faster and improved Software updates.
OnePlus will be bringing software teams together in order to achieve a single, optimal user interface that will be probably called H2O or Water OS ( May be :p ).
According to OnePlus-
The main benefit of combining our team resources is to speed up software updates. We know we have some room to continue improving there, and this is an important step in the right direction.
If you guys don't know then Oxygen OS is based on Android Vanilla, where as Hydrogen OS is like Chinese skinned UI. So merging both will result in a UI which will be both Skinned and little bit like Stock. After all OnePlus is a Chinese company, They will probably make the OS more like MIUI Style.