"All messages will be accessible in the new messaging app".
However the company is making some changes to Hangouts that appears to be trying to make the app more streamlined, and that is by possibly removing the SMS feature. If none are available, then they will be immediately redirected to Google Play store to find another SMS messaging app they can use.
Google notes that the shutdown won't impact Google Voice users and Google Fi subscribers who use Hangouts for messaging.
The move is part of the company's refocus of Hangouts towards the enterprise market, which will see the service split in two to become Hangouts Chat and Hangouts Meet. The app will now be promoted for its video communication capabilities rather than text messages. The next to go are previews of Picasa photos and chat pictures; Quick Links, which provided fast access to emails and folders; the ability to quote selected text; Smart Labels, which automatically categorized newsletters, promotions, receipts, and notifications; and Yelp review snippets. You'll be prompted to select a new default messaging app from your list of downloaded apps.
Luckily, those with Google Voice numbers won't be affected. So will the Google Voice Player, which provided an audio preview of incoming voice mails. Google wants users to use Android Messages for SMS (or any other SMS app that isn't Hangouts). Fortunately, Google has at least seven other messaging services that you can use, including Allo, Duo, Hangouts, Android Messages, Voice, and Supersonic Fun Voice Messenger, so you've got plenty of other options to use going forward.
Even though the e-mail is not confirmed, it does looks believable as Google would anyway alert its enterprise clients before the general ones about the upcoming changes.
Google didn't respond to a request for comment about future chat app plans. Stay tuned with us more information on the news.