I'm using the following syntax in my shared libraries and testing pipelines, both worked as expected in versions previous to v2.277:
emailext body: '''${SCRIPT, template="groovy-html.template"}''', mimeType: 'text/html', subject: "${SUBJ}", to: "manager@mailer.com", replyTo: "qa@mailer.com", recipientProviders: [[$class: 'FirstFailingBuildSuspectsRecipientProvider'], [$class: 'CulpritsRecipientProvider'], [$class: 'RequesterRecipientProvider']]
the pipelines weren't changed, i just applied the upgrade to v2.77. The result was the body containing the literal value:
${SCRIPT, template="groovy-html.template"}
The template was not ijected anymore.
The revert to v2.66 restored the functionality (Formatted mail with deploy status, changes, tests results).
Please provide a detailed description so that others can duplicate the problem you're seeing.
I'm running Jenkins 2.277. The simple email notification that I've configured on job completion is working as expected. I'm able to open the job configuration, edit the email notification, save the configuration, and it sends email notification.