Yes, from 2021.1 it is possible to specify the Color Space for each texture. You need to go Live View menu materials/Octane Texture manager, and check that the Color Space is not set to
No-color data, then change it to
Linear sRGB-Legacy Gamma.
in 2021.1 there is also a new
White Light Spectrum menu in the kernel panel, and by default is set to
D65.
You need to switch to
Legacy/Flat to have the same result as before:
ciao,
Beppe