I upgraded my JIRA Service Desk to a version that was not supported by my old license, so I have bought a new license, but JIRA won't start up now, so I can't apply the license.
The exact message is:
License Too Old For Build: We found a problem with your JIRA license
Your current JIRA Service Desk license doesn't allow you to upgrade to this version of JIRA (7.4.4). JIRA Service Desk expired on 17/Mar/17 1:00 PM, and you can currently only upgrade to versions released prior to this date. Alternatively you can renew your license at my.atlassian.com which will allow you to upgrade to this version of JIRA (7.4.4). You can enter your new license here.
See our documentation for more information on licensing errors.