No criminology is not an optional for UPSC civil services exam for the complete list of optional and exam paper pattern of UPSC please visit the link given below

https://competition.careers360.com/articles/upsc-ias-syllabus

the official notification for UPSC 2020 is released and the prelims is said to be held on 31st May 2020

No, Criminology is not an optional for UPSC.

https://www.nextias.com/optional-syllabus

This is a list of optional subjects.

Hope this helps,