Massive number of PHP Warnings after update to PHP 8.1

After we upgraded our site to PHP 8.1 from 8.0 we started to get a massive number of PHP Warnings in our error logs:
“PHP Warning: Undefined array key “email_role” in /home/runcloud/webapps/OurSite/wp-content/plugins/invite-anyone/by-email/by-email.php on line 422″

So I had to change the function invite_anyone_access_test() to this:

function invite_anyone_access_test() {
global $current_user, $bp;

$access_allowed = true;
$iaoptions      = invite_anyone_options();

if ( ! is_user_logged_in() ) {
    $access_allowed = false;
} elseif ( current_user_can( 'bp_moderate' ) ) {
    // The site admin can see all
    $access_allowed = true;
} elseif ( bp_displayed_user_id() && ! bp_is_my_profile() ) {
    $access_allowed = false;
} elseif ( isset( $iaoptions['email_visibility_toggle'] ) && 'no_limit' === $iaoptions['email_visibility_toggle'] ) {
    // This is the last of the general checks: logged in,
    // looking at own profile, and finally admin has set to "All Users".
    $access_allowed = true;
} elseif ( isset( $iaoptions['email_since_toggle'] ) && 'yes' === $iaoptions['email_since_toggle'] ) {
    // Minimum number of days since joined the site
    $since = isset( $iaoptions['days_since'] ) ? $iaoptions['days_since'] : 0;
    if ( $since ) {
        // WordPress's DAY_IN_SECONDS exists for WP >= 3.5, target version is 3.2, hence hard-coded value of 86400.
        $since = $since * 86400;

        $date_registered = strtotime( $current_user->data->user_registered );
        $time            = time();

        if ( $time - $date_registered < $since ) {
            $access_allowed = false;
        }
    }
} elseif ( isset( $iaoptions['email_role_toggle'] ) && 'yes' === $iaoptions['email_role_toggle'] ) {
    // Check if 'email_role' is set before accessing it.
    if ( isset( $iaoptions['email_role'] ) && ! empty( $iaoptions['email_role'] ) ) {
        $role = $iaoptions['email_role'];

        // Minimum role on this blog. Users who are at the necessary role or higher
        // should move right through this toward the 'return true' at the end of the function.
        if ( isset( $iaoptions['minimum_role'] ) && $role ) {
            switch ( $role ) {
                case 'Subscriber' :
                    if ( ! current_user_can( 'read' ) ) {
                        $access_allowed = false;
                    }
                    break;

                case 'Contributor' :
                    if ( ! current_user_can( 'edit_posts' ) ) {
                        $access_allowed = false;
                    }
                    break;

                case 'Author' :
                    if ( ! current_user_can( 'publish_posts' ) ) {
                        $access_allowed = false;
                    }
                    break;

                case 'Editor' :
                    if ( ! current_user_can( 'delete_others_pages' ) ) {
                        $access_allowed = false;
                    }
                    break;

                case 'Administrator' :
                    if ( ! current_user_can( 'switch_themes' ) ) {
                        $access_allowed = false;
                    }
                    break;
            }//end switch
        }//end if
    }
} // <== This closing bracket was missing
elseif ( isset( $iaoptions['email_blacklist_toggle'] ) && 'yes' === $iaoptions['email_blacklist_toggle'] ) {
    // User blacklist.
    if ( isset( $iaoptions['email_blacklist'] ) ) {
        $blacklist = wp_parse_id_list( $iaoptions['email_blacklist'] );
        $user_id   = intval( $current_user->ID );
        if ( in_array( $user_id, $blacklist, true ) ) {
            $access_allowed = false;
        }
    }
}

return apply_filters( 'invite_anyone_access_test', $access_allowed );

}

It would be great if you could handle this issue in a coming release.