The company said it will turn on the "Chat preferred" setting for any customers who have not already done so, making Google Chat the default chat application beginning March 22.
"This means that when users visit classic Hangouts in Gmail on the web or the classic Hangouts mobile apps, they will be directed to Chat," the company said in a blogpost.
"Hangouts.google.com will continue to work. It is not possible to opt out of this change. If you would like to export your classic Hangouts and Chat data, learn about exporting your organisation's data," it added.
After domains are upgraded to "Chat preferred", all classic Hangouts applications, except hangouts.google.com, will be disabled.
Additionally, the "Chat and classic Hangouts" and "Classic Hangouts only" settings will be removed from the Admin console.
Messages sent in classic Hangouts will continue to be retained and held according to policies set for Chat, and searchable and exportable with Gmail search in Vault.
Messages sent in Chat are subject to retention rules and holds you set for Chat and searchable and exportable with Chat search in Vault.
The company also mentioned that except for a few special cases, all the conversation history from Hangouts will be available in Google Chat.
However, starting mid-March 2022, any newly created spaces in Google Chat within domain will not appear in classic Hangouts.