Undefined array key

When I upgrade our PHP version to 8.1, I get multiple warnings related to the array key being undefined. I assume it’s coming from the Bookshelves plugin based on the warning.

Following are two examples appear above the header:

1. Warning: Undefined array key “lbs_cat_URL” in /…/…/…/…/wp-content/plugins/library-bookshelves/functions.php on line 91

1. Warning: Undefined array key “lbs_cat_CDN_URL” in /…/…/…/…/wp-content/plugins/library-bookshelves/functions.php on line 107

For the time being I have downgraded PHP to correct the issue. I also assume it’s specific to our site, since I can’t find any other posts about it. I am just hoping someone else has some insight.

Any assistance is appreciated.

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