Checkboxes

Field code

 %{issue.cfnnnnn}

Read text

Returned value	List of the Checkbox values which were chosen out of multiple values using checkboxes
Output data type	TEXT
Example output	Checkbox 1,Checkbox 2

ID field code

%{issue.cfnnnnn.id}

Returned value	List of the Checkbox IDs which were chosen out of multiple values using checkboxes
Output data type	NUMBER LIST
Example ID output	10012, 10001

Valid text input
Valid numerical input	Comma separated list of IDs for the options available for this custom field
Example input	10003,10004