Personal Access Token was supported by JIRA since JIRA Server 8.14. It requires authentication using bearer token instead of the old basic auth. Jenkins's Jira plugin has already added the support back in May: https://github.com/jenkinsci/jira-plugin/commit/851f553d91ea34cdf9bbb4a2be5cf37e74f64a2d. It would be great if the support can also be added to Jira-ext plugin.