Hi,
It is not compulsory. But, why do you want to waste an opportunity to save money. It will help the employer to save 8.33% of employer share paid to new employees.
The eligibility concept is given below:-
1. The employee strength of the given month should not be less than the employee strength in the month of March of previous FY.
2. The employee should be a fresher. ie., no previous employment records in PF.
3. The employee should receive salary (gross) less than Rs. 15,000.
If all the above conditions are met, then you can apply for PMRPY registration for the particular employee in the given month.