Logical operators

I found a solution to this problem.

Modify your class-core.php file on around line 74. Change the whole condition_query_string to:

private function condition_query_string( $value, $match ) {
	if( strstr( $value, ':' ) ){
		list( $qs_key, $qs_value ) = explode( ':', $value );

		$match = ( empty( $match ) ) ? 'exact' : $match;

		# Check if GET value matches given value
		if ( ! isset( $_GET[ $qs_key ] ) || false === $this->check_value( $_GET[ $qs_key ], $qs_value, $match ) )
			return false;

		return true;
	}
	elseif( strstr( $value, '!' ) ){
		list( $qs_key, $qs_value ) = explode( '!', $value );

		$match = ( empty( $match ) ) ? 'exact' : $match;

		# Check if GET value doesn't match given value
		if ( ! isset( $_GET[ $qs_key ] ) || false === $this->check_value( $_GET[ $qs_key ], $qs_value, $match ) )
			return true;

		return false;
	}
	else{
		return false;
	}
}