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Once you create a template, it will be selectable in “Release Notes” pages for Bundles and “Component Versions”.
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Rendering Release Notes With REST API
You can not only create/update/delete release notes using REST API but you can also render them. You can use following request format to render them.
GET {JIRA_BASE_URL}/rest/api/com.deniz.jira.mapping/latest/releasenotes/render/bundle/{BUNDLE_ID}?templateId={TEMPLATE_ID}
GET {JIRA_BASE_URL}/rest/api/com.deniz.jira.mapping/latest/releasenotes/render/
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mapping/{MAPPING_ID}?templateId=
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{TEMPLATE_ID}
To get list of all templates you can use following method.
GET {JIRA_BASE_URL}/rest/api/com.deniz.jira.mapping/latest/releasenotes/template/summary