PHP 8+ error

Hello!
I get following information in debug mode:

Fatal error: Uncaught TypeError: array_slice(): Argument #1 ($array) must be of type array, bool given in …/wp-content/plugins/get-user-custom-field-values/get-user-custom-field-values.php:140 Stack trace: #0 …/wp-content/plugins/get-user-custom-field-values/get-user-custom-field-values.php(140): array_slice(false, 0, 1)

1 …/wp-content/plugins/get-user-custom-field-values/get-user-custom-field-values.php(69): c2c_get_user_custom(0, ‘[ownfieldname]‘, ”, ”, ”, ”, ”)

21 {main} thrown in …/wp-content/plugins/get-user-custom-field-values/get-user-custom-field-values.php on line 140

Can you help me?

Kind regards,

Klaus