Upgraded PHP and now Error

I upgraded my PHP to 7.4 and now I am getting this error at the same spot on most pages.

Notice : Trying to access array offset on value of type bool in /hermes/bosnacweb02/bosnacweb02bz/b227/ipg.paisleyapothecarycom/wp-content/themes/shapely/inc/extras.php on line 760

Hi there

It’s just a notification, there is nothing to worry about it, just disable error message from the wp-config.php its bad habits to have enabled them