This validator can block a transition based on the state and the number of an issue's sub-tasks.
The validator only makes sense when used in a workflow used by standard issue types.
You can specify multiple filter criteria that will be "and concatenated". Per default, all sub-tasks must match the combination of all criteria.
Configuration
If you want to use this functionality in a condition instead, have a look at the following condition: Condition on sub-tasks
Use cases and examples
If you still have questions, feel free to refer to our support team.