If an employee's gross salary gets increased to more than 21,000 - how long should the employer pay the ESIC?

Hi Everyone, If an employee's gross salary gets increased to more than 21,000 and he comes out of the ESIC limit, so how long should the employer pay the ESIC. Will he pay the ESIC for the next 3 months only or will it extend to the next quarter also.
Eg: If an employee's salary gets increased to more than 21000 in the month of Feb so is the employer supposed to pay the ESIC till march or will he pay for the next quarter as well.

Even if salary ceiling of Rs.21000/- under ESI is exceeded by way of hike in salary, the concerned employee has to necessarily complete the contribution period, that is to say.
April - September
October - March are the two contribution periods.
As per your post, the employee's salary is increased with effect from Feb , so you have to
deposit his contribution for March also, in the month of April.