The second option is to update the app from within itself.
Step#1: Open GB WhatsApp app.
Step#2: Tap the three-dot icon.
Step#3: Click on Fouad Mods.
Step#4: Choose Updates settings.
Step#5: ‌Click on Check For Updates.ADVERTISEMENT
If there is an update found then go ahead with the update process.
Step#6: Select the option Web Download.
Step#7: Open it with any browser you have.
Step#8: Find the GB WhatsApp package & tap the Download button.
Step#9: Press the Download button.
Step#10: Wait till the APK gets downloaded.
Step#11: Open the GBWhatsApp APK file.
Step#12: Allow installation from unknown sources.
Step#13: Tap Install to update the app on your device.
Step#14: Wait till the process gets completed.