Hi Jayaramu,

Greetings to you!

To add a namespace prefix for a managed package, see Register a Namespace Prefix (https://help.salesforce.com/articleView?id=register_namespace_prefix.htm). If you don’t have a registered namespace, add the default namespace of c__. To test and ensure that your namespace prefixes work, enable this critical update. Test any pages that have custom query parameters and that navigate to a URL containing /lightning/. If you have managed packages, test pages from within and outside of managed packages. If you run into issues, ensure that you've prefixed the values with a namespace. If you continue to have issues, contact Salesforce Customer Support.

After you add namespace prefixes, enable the critical update. From Setup, enter Critical Updates in the Quick Find box. Then select Critical Updates. For Add a Namespace Prefix to Query Parameters and pageReference.state Properties, click Acknowledge.

However, Date for the Critical Update "Add a Namespace Prefix to Query Parameters and pageReference.state Properties" has been revised from Jan to May 17, 2019

In Salesforce Org under the Critical Updates you may notice the Auto-Activation Date for the Critical Update is Mentioned as January, which our Product Team has revised in Spring '19 and the new date for Auto Activation is set to May 17.

Reference: https://releasenotes.docs.salesforce.com/en-us/spring19/release-notes/rn_forcecom_general_namespace_prefix_cruc_reminder.htm

https://help.salesforce.com/articleView?id=000273993&language=en_US&type=1

I hope it helps you.

Kindly let me know if it helps you and close your query by marking it as solved so that it can help others in the future. It will help to keep this community clean.

Thanks and Regards,
Khan Anas