Gmail's native Offline mode is making its way to users' accounts
 

You might have access to Google's native Offline mode very, very soon if it hasn't landed on your account yet. The feature, which debuted as part of Gmail's redesign at Google I/O, has started rolling out to users. If you're using a work or school ac...

https://www.engadget.com/2018/05/15/...-mode-rollout/