Being one of the key projects on Blender's development roadmap for 2023, this phase is transitioning Blender from the outdated OpenGL graphics API to Vulkan, its successor. Vulkan is expected to become the default API for both viewport rendering and Eevee, Blender's real-time renderer, on Windows and Linux, with support for both AMD and NVIDIA GPUs. This transition to Vulkan not only future-proofs the software, as OpenGL is no longer actively developed, but also brings new capabilities.
In the Blender developers' blog, examples are given such as GPU-accelerated texture painting, HDR display support, and the shift from screen space to ray tracing effects in Eevee.

However, at the moment, things are not entirely smooth sailing. Vulkan is described as "fairly experimental" and comes with a notable list of known limitations. According to the initial release notes, its performance is at "around 20% of what we want to achieve," but developers intend to focus primarily on stability and platform support.
Thanks to this transition, Blender joins the relatively small group of CG applications that have adopted Vulkan, along with game engines like Godot and Open 3D Engine. Among other DCC tool developers, Maxon shifted Cinema 4D's viewport from OpenGL to closed-source DirectX in 2021, previously adopting Metal on macOS. Other applications, such as Maya, already had DirectX viewport display modes.
Blender is compatible with Windows 8.1 and above, glibc 2.28 and above for Linux, and macOS 1.15 and above. The stable release of Blender 4.0 is expected in November 2023, followed by Blender 4.1 in March 2024.