Different results are obtained when retrieving an issue via the REST api compared to XML. Attached are the results obtained from the following two URLs:

• GET http://jira.atlassian.com/si/jira.issueviews:issue-xml/JRA-23969/JRA-23969.xml
• GET http://jira.atlassian.com/rest/api/latest/issue/JRA-23969

Observations:

• xml contains resolution, omitted from json (looking at other issues, I see that resolution is included in the json if the issue is actually resolved. For unresolved issues, however, the value appears to be omitted)
• xml contains field values for Participants (customfield_10150), json contains no values for this field
• json contains values for "Support Request Message (IssueType:Bug)" (customfield_10250). This field is shown in the xml with no corresponding ID and no value.
• json contains a field value for "Test Issue Creation Warning" (customfield_10301). This field is shown in the xml with no value.
• json shows many more custom fields that aren't in XML (none appear to have a value associated with them, so perhaps that's why they're omitted?)
• json shows information about watchers; xml does not
• json shows fixVersion; xml does not unless there's a value