Phase-6 : Deployment / Release / Delivery :
Once the Test Engineer approves the build and it is stable then the Project manager will deliver the build to the client.

The client will deploy the build in the Stage Environment.

“Stage Environment” is common environment for both the Client and Testing Team(Company). Both will perform testing on the stage environment. If the application is stable, then the client will deploy the build in the Production Environment.

When the build is moved/deployed in the Production Environment then we can conclude that project was accepted by the Client and the Project got successes.

When the build is moved to the production or Live Environment then the Maintenance of the project will be started.

Phase-7 : Maintanance :-

Maintenance is depends based on the Project Agreement. (It could be 5 years, 10yrs, or 15yrs…etc.)
The company is responsible for two things/activities. 

1) If any bug is identified by the client, the client will send the bug to the company (BA, Testing Team, Development Team, and PM).

From the company, someone will send an acknowledgment mail will be sent to the mail client within the “Turn Around Time”.
It TAT could be 12hours, 24hours, 48hours based on the project agreement.

The acknowledgment mail contains when we are going to fix the bug and deliver it to the Client.

2) If any updating is required for the application, then the client will send the CR- (Change Request/ Change Requirement) to the company.
The company is responsible to update the CR in the build. 
The company will charge for extra budget/money for the CR.