Hello, 

CBSE registration 2019: The registration process for private candidates of class 10th, 12th has been started at cbse.nic.in by the Central Board of Secondary Education (CBSE). The registration has been commenced for the examination that are scheduled to take place in February/March/April 2019.

The CBSE Improvement Exam takes place in the following year and can be taken in one or more subjects in the succeeding year only after clearing the subject in Class 12.

According to me it's exam will be conducted in January 2019 . But for better please contact to your school's staff .