Gmail's new native Offline mode is now rolling out to users, and to enable it you need to do a teeny bit of fiddling.
Click Save Changes and you're done.
Read, respond to, and search your Gmail messages even when you aren't connected to the Internet. Previously this feature was available for Chrome users as an add-on for the browser, but this naturally hinders performance like most add-ons.
You must also select whether you want to keep that offline data stored on your computer after you've logged out of your Google account or if you want it removed each time you log out. If that's the case (or you're simply somewhere with cruddy Wi-Fi), you can still gain some semblance of productivity with a new option in Gmail: offline mode. After switching to new Gmail, go to Settings and selected Offline from the menu and then Enable offline mail from the options.
Using Gmail offline can help those who travel regularly or do not have regular access to an internet connection.
Under "Privacy and security", click Content settings.
Google is rolling out native Offline mode for Gmail users
To delete the account data, users must first disable offline mode and save the changes.
For the terminally stupid, it's probably worth iterating that "offline" still means your emails won't send until you're back online.
Nudges are on by default, but you can switch them off by visiting Gmail's Settings page.
Before you go all-in on offline mode, there are a few limitations you should know about. You can find this option by opening the Chrome Settings menu, scrolling down to Advanced, and then clicking on the Clear Browsing Data menu item. This feature has been made available, as of now, only on the desktop and is compatible with Google's Chrome browser (version 61 and above will only support this feature).
Once you've chosen how you want to set up your offline sync click Save Changes, but don't close out of Chrome yet!