RIFE has finally gotten another big update: It can now interpolate with any factor. It still has to be an integer (whole number) but apart from that you can now chose anything - 3x interpolation, 5x, 10x, whatever. It seems to get unstable at more than 16x but I don't think you'll need that anyway.
There is also a new RIFE model (3.9) which is 23% faster than 3.8, 54% faster than 3.1, and compared to 2.3 it's twice as fast! (Tested with 1080p 2x interpolation).
Additionally, WEBP VP9 encoding, while still being slow (that's just how VP9 is...) is now more efficient by doing two-pass encoding.
Full changelog on Discord and in Flowframes.