During the latest round of updates (September 2019), we removed the Google Plus share icons as Google Plus has ceased to exist.
If you still had the Google + icons enabled and updated, you may see an error that looks something like this:
Notice: Undefined index: googleplus in [....] on line 1436
Fixing this error is quite simple. Here's how:
1. Open the Customizer (blue "Customize Your Site Button" or go to "Appearance > Customize").
2. In the Customizer, click on the Theme Options tab.
3. Click on the Post Settings tab.
4. Scroll down to the Post Extras section.
5. Find the Sharing Services settings.
6. Click on the "x" next to any of the listed services to remove it.
7. The field will reset and remove the error.
8. You can click on the box and select the service your removed to add it back.
9. Click the blue Publish button to save the changes and officially remove the error.