JIRA 4.2.1 Upgrade Guide
Upgrading from JIRA 4.2 to 4.2.1
Please follow the JIRA general upgrade instructions.
When you download JIRA, please note that the filename now includes the build number, e.g. "b588" in the filename "atlassian-jira-enterprise-4.2.1-b588-windows-installer.exe". This has no effect on the JIRA directory structure or on the upgrade process.
Please note that the inclusion of the build number has also been applied to the name of JIRA artifacts deployed to Maven and to the versions specified in the JIRA POMs.