Retention of Classic Hangout Chats Made Easy in Google Vault
The retention and hold policies of the Hangout chats have been separated from the mail retention and hold policies. Google has introduced a feature in order to preserve them both for classic hangout and chats.

Google Vault is a service that is used to fulfill the eDiscovery needs of an organisation. It is used to hold, retain, search and export data for archiving.
The type of data that can be archived using Google Vault are : -
1. Emails
2. Classic Hangouts Chats with turned on history and Google Talk chats on record
4. Google Drive and Team Drive Files
5. Conversations of Hangouts Chat
6. Hangouts Meet recordings
Google has introduced a new way of archiving the Classic Hangout and Chats.
Earlier mail retention rules and holds use to protect both mail and chats in Classic Hangouts. But now onwards, in place of mail retention rules and holds, Hangout chat retention rules and holds will protect chat messages in both classic Hangouts and Chat. This feature is going to be implemented from April 16, 2019.
In order to preserve messages in classic Hangouts, before April 16, 2019, we have to copy any existing Mail holds (that apply to messages in classic Hangouts) to Hangouts Chat in Google Vault. This feature helps to ensure all your messages in classic Hangouts and Hangouts Chat are preserved by the same Vault policies as your classic Hangouts messages are today.
Let’s see how we can do this from the Google vault:
1.First go to the Google vault, you can use ediscovery.google.com.
2. You will see the list of vault matters, from them choose the one that is containing the holds for Gmail.
3. After that go through the holds of that matter and select mail holds among them.
4. After the selection click on the option “ Copy holds to Hangouts Chat” on the top.
Point to be noted:
While creating the holds for Gmail, you get the option to select the date range for the messages. But in case of Hangout holds it is not supported, so the mail holds that contain date ranges or search terms will not be copied with the hold.