Applicable to:
1) Android
To switch on auto-update for Zeemart on Android:-
Go to Google Play Store app.
2. Tap on Menu.
3. Tap on My apps & games.
4. Select the Zeemart app.
5. Tap on More (the 3 dots).
6. Toggle "Enable auto-update".
Refer here for the full instruction from Google.

2) iOS
To switch on auto-update for Zeemart on IOS:-
Go to Settings.
2. Tap on your profile name.
3. Go into iTunes & App Store section.
4. Toggle the "App updates" button.
Refer here for the full instruction from Apple.