Some earlier reports suggest that Qualcomm will announce the Snapdragon 775G and Snapdragon 875 chipsets in early December. So, current speculations believe that this upcoming Redmi K40 series will be powered by these un-announced chipsets.
Last year’s Redmi K30 standard version was the first one to be powered by Snapdragon 765G whereas the Pro version is powered by Snapdragon 865. So, with the Redmi K40 series, the company may bring the Snapdragon 775G to its base model whereas the Pro model may feature Snapdragon 875 SoC.
Xiaomi is yet to reveal any details regarding the Redmi K40 series but reports believe that it may go official before the end of 2020.

Alleged Redmi K40  Xiaomi M2011K2C  bags MIIT certification - 27