title: Jira: How to obtain the previous value for a custom field in a custom IssueEventListener
body: <p>So how does one obtain the <strong><em>previous</em></strong> value of a <strong><em>custom</em></strong> <strong><em>field</em></strong> in a Jira IssueEventListener? I am writing a custom handler for the issueUpdated(IssueEvent) event and I would like to alter the handler's behavior if a certain custom field has changed. To detect the type of change I would like to compare the previous and current values.</p>
  
  <p>(I'm am not asking about how to obtain its <em>current</em> value - I know how to get that from the related Issue)</p>
  
  <p>I am developing against Jira 4.0.2 on Windows.</p>
  
  <p>Is the best way to scan the change history for the last known value?</p>
  
  <pre><code>List changes = changeHistoryManager.getChangeHistoriesForUser(issue, user);
  </code></pre>