Get information about categories.
| Name | Required | Default | Description | Example |
|---|---|---|---|---|
| groupID | true | N/A | forum group context | 12 |
| parentCategoryID | false | parent id of categories to assure exists | 12 | |
| format | false | specified at session open | response output format (json|xml|csv|gchart) | json |
| {groupID} may not be null | -4 |