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With the latest release of Connector for Salesforce & Jira (Cloud), users can now control the visibility of JSM comments through Salesforce package settings.
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Limitations
Connector for Salesforce & Jira (Server) currently does not work with the Jira Service Management comment visibility setting.
However, Jira Issue comments can be viewed in Salesforce through a dedicated Visualforce panel and Chatter. For more details about this configuration, visit this page.
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Next steps
If you have not installed the Salesforce package, go to Installing the Salesforce Package for Salesforce & Jira Cloud Connector.
Otherwise, view Setting up a connection to Salesforce.