I got this mail from Apple.
Your iOS Distribution Certificate will no longer be valid in 30 days. To generate a new certificate, sign in and visit Certificates, Identifiers & Profiles.
I get some information from StackOverFlow but I want to know what I need to do if I modify my existing app. Will I able to update in future the same app with new certificate and new profile. Is that I need to revoke and generate the new certificate. Thanks for your help and comments.
Harjot Singh :
As per new updates, you don't need to renew the certificate as a separate action. The renewal is based on the expiration of the Apple developer account. By taking the action of renewing your membership, this will automatically renew your certificates.",
2019-02-21T07:04:49