Google confirmed that Inbox, its experimental email service, will be discontinued next year.

The service launched in October 2014, but it didn’t become widely available until May 2015. Inbox was designed as a place for Google to test new features. It infused organized bundles of messages based on category, an ‘Undo Send’ button, task integration, and calendar syncing.

Over the years, the Mountain View-based company transitioned Inbox’s most successful features over to Gmail. Google says additional features will jump to Gmail in the coming months.

Gmail hosts more than 1 billion active users. It is, of course, the world’s preeminent leader in email.

In the meantime, you’re still able to use Inbox. The service won’t be shut down until March 2019. But that will definitely mark the end of Inbox’s tenure as a first-party alternative. All users will need to return to Gmail, which shares many of the same features, or switch to a third-party service that syncs with a Google Account.

Farewell, Inbox. Take up a cozy space next to Allo in Google’s graveyard.