Replacement for ATWINC1510-MR210PB

Is there a replacement option in the works for the WiFi module for the SITcore as the existing Microchip offering is now NRND and end of life?

Still in production
https://www.microchip.com/en-us/product/atwinc1510

You are probably referring to the specific firmware version, which you can download into any module.