Gratuity payment - the ex-employee has not yet encashed the cheque - what course of action?

We being an employer issued cheque for gratuity payment and employee acknowledged the same. But now it is observed, the ex-employee has not yet encashed the cheque.
Please inform, what course of action further we need to do as an employer?

Once you have made payment to the concerned employee and obtained his acknowledgement towards gratuity payment settlement, the responsibility of yours as an Employer is completely fulfilled.
Being a considerate employer, you can write a letter to employee to his last known address as well as his permanent address informing that the payment instrument is not yet encashed and advising him to encash the same as soon as possible and keep a copy alongwith the gratuity payment settlement documents.