Version 1.9.1

UPDATE: As of Mar 27th 2019: NIFI-6150 has been identified which means 1.9.1 can result in content repo being exhausted and not cleaned up properly.  We will produce a 1.9.2 as soon as the fix is confirmed.  Recommend not updating until then.

Version 1.9.1 of Apache NiFi is a bug and stability release.

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A full list of issues that were resolved can be found at https://issues.apache.org/jira/secure/ReleaseNote.jspa?projectId=12316020&version=12333089