Not a preview.
It has been in the public releases since 1.29.0.6244 in September 2022 (Announcement thread).
As mentioned by @JaysPlex , you get hardware accelerated HDR to SDR tonemapping.
Another benefit is the use of zero-copy transcoding on Nvidia GPUs. Transcoding, whether HDR or SDR, is more efficient, as less data is moved across the system bus.
You can install the 64-bit version over the 32-bit version. The installer will detect and remove the 32-bit version.
If you fall back from 64-bit to 32-bit, you must first uninstall the 64-bit version (standard Windows uninstall). The installer for the 32-bit version has not been updated and does not know to look for the 64-bit version.
