Issue in Laravel 7

I am getting this error: production.ERROR: Array and string offset access syntax with curly braces is deprecated {"exception":"[object] (ErrorException(code: 0): Array and string offset access syntax with curly braces is deprecated at ...../vendor/campaignmonitor/createsend-php/class/services_json.php:156

Is there a fix?

To upload designs, you'll need to enable LFS and have an admin enable hashed storage. More information