For now i recommend to use CSP 0.2 till CSP 0.2.3p1. And i think that is for the next months.
The new CSP version has a new feature called Linear Gamme Space (LCS). It will solve issues with AC rendering, BUT therefore the core shaders were reinvented. CSP now have 2 shader sets, the old shaders like CSP 0.2 - 0.2.3p1 and new shaders which support LCS.
The shaders are switched by activating/deactivating LCS in weatherFX settings. So actually it could be possible to run the old mode with Pure without problems.
Pure will not have LCS in the NEXT MONTHS. Pure must be rewritten from the ground, because everything is changed with the core shaders and currently i'm not sure if this is worth it.
It is the biggest change since the first release of CSP and it affects all parts of Pure in a very negative way. It will need a huge amount of time to fix all new problems with it.
So actually CSP without LCS should be compatible with Pure, but there are other changes in CSP which will influence it negatively.
So I ask for your understanding, that Pure is only compatible for CSP versions from 0.2 to 0.2.3p1 for a long time. If you discover any problems with the new CSP and Pure, please switch back to a supported CSP version and try again, before you report problems.
If you want to test LCS and its differences to the old shaders, please use the "default" weather style. You can switch LCS in weatherFX settings "Use linear color spcae fix". And please also switch back to Pure and make your own thoughts about what is more realistic...