Ogre-next 2.1, 'breaks' with its legacy and starts moving forward, supporting the newest render systems D3D11 or GL3+ and Metal (and is prepared for Vulkan and D3D12). In addition, it supports cutting edge rendering techniques such as Physically Based Shaders (PBS), Instant Radiosity, Parallax Corrected Cubemaps, Screen Space Reflection (SSR), Forward Clustered Shading and Hybrid Rendering (Deferred + Forward). Ogre V2 is also capable of rendering high-quality shadows using Exponential Shadow Maps (ESM).
This is also the trigger to start with a new homepage, dedicated to all development from Ogre versions Ogre V2.1 and beyond.
For a general comparison of current Ogre versions, see the "What version to choose" page.