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- To create new validator go to Jira Administration > Issues > Workflows.
- Click Workflows. Click Edit for certain Project you'd like to add validator to.
- Select Diagram view.
- Select the transition you'd like to add validator to and click. Configuration panel appears. Select Validators.
- Click Add validator.
- Select validator type you'd like. Click Add.
- Add parameters to validator. Click Add.
- That's it. Now the transition requires saved criteria to be valid.