Work offline in the new Gmail using Chrome browser

May 16, 2018

We can guarantee you’ll want to work on the go, but we can’t guarantee you’ll have Wi-Fi. Fortunately, native offline capabilities in the new Gmail make it possible to work without interruption—even when you don’t have an internet connection. Starting now, if you're using the new Gmail in a Chrome browser (v61 or higher) can search, write, delete, and archive up to 90 days of messages, even when you're offline.

Source: G Suite Updates