What is the eligibility of an employee to attain bonus?

Can anybody elaborate the eligibility of an employee to attain bonus.

Section 8 of the Payment of Gratuity Act deals with this question.
The Payment of Bonus (Amendment) Bill, 2015 notified:Increase in the Eligibility Limit under clause (13) of Section 2 and Calculation Ceiling under Section 12 of the Payment of Bonus Act, 2015

Hi
By virtue of amendment namely: The Payment Of Bonus (Amendment) Act, 2015 which came into retrospective effect from 1st April, 2014 an employee drawing less than Rs.21,000/- per month is eligible for bonus under The Payment of Bonus Act.
For the purpose of calculation of bonus the employee salary will be taken as Rs.7000/- or the minimum wages whichever is higher.
Various High Court has given stay on the retrospective effect of applicability of the amendment. That means the employer has to comply with the amended provision from 1st April, 2015.
A copy of the aforesaid amendment is attached herewith.
Regards
P.S.Lakshmanan
S. G. Management Services
(PAN INDIA Consultant – Labour Law Compliance,
PF, ESI, P Tax, Benefit Management &
POSH COMPLIANCE) - KOLKATA

If Company mentions bonus pro-rata , monthly basis in appointment letter , " AS PER BONUS ACT " etc , then Irrespective of the effective date of its declaration or actual disbursement etc , company is liable to pay the same to the employee ( Person ) , and not to his/her status as employee i e it should be irrespective of his current status as employee OR he is EX , OR RETIRED , OR have resigned from the Company .
And IF this is in-line , labour commissioner or Hon Court should take a call .
Please let me know IF EMPLOYERS DISCRETION PREVAILS OR LAW OF THE LAND ?