Design suggestion on updating our engine

so we have our game engine currently powering our flagship product and other games, and the backbone of it was written in OpenGL Es and can both compiled in ios and android as both platform shared it. (and since its OGL, we can code in desktop with/without simulator but straight up desktop app).
Its fairly straightforward as both android and ios shares opengl in native form (NDK for android and straight C++ in ios). In this way, the game can be written in straight up C++ and will/can run on both platforms.

but now we are considering updating …