atlassian servicedesk 3.1.9 (x64) to 3.11.1 upgrade - any issues?

[IT Ops]

Hello all, 

Planning to upgrade our JIRA core, Software and Service Desk installation via the downloadable installer. 

Current JIRA/Core is 7.1.9, Service Desk is 3.1.9, have looked for an upgrade matrix (which versions to step through or what direct upgrades are supported) but could not locate one that had that detail. 

We're running on x64 Windows, MS-SQL at the back end. 

If it's Ok to run the installer download (instead of the individual OBR files) that would be great, if not and there is a version we need to step to before upgrading to the most recent that would be good to know as well.

[Amirul Ikhwan Omar]

Actually what we'll need is to basically upgrade JIRA Core with the installer and then upgrade JIRA Service Desk directly in the UI without the installers.
In order to do this, I'd recommend downloading the installer for JIRA core which will automatically install JIRA Core then access Administration > Applications and hit the Upgrade button on JIRA Service Desk. There is no intermediary version needed for the upgrade.