Considerations when moving from a service release to a feature release

When working with QlikView or Qlik Sense you may be using a service release or a feature release version of the product.

The feature releases of Qlik software include all the latest features of the product, but are more likely to contain minor bugs. The service releases are more focused on stability and recommended if your main expectation is stability and not new features.

For more detailed information about the differences between a service release and a feature release version please see the related article: Qlik Product Release Tracks

In some cases, when you report a system bug in QlikView or Qlik Sense and your server is on the service release track, the system bug fix may not be possible to implement or merge into the next service release.
This can be due to high risk where the bug fix may be dependent or impacting on other components in the existing service release.

In such situations, if your server happens to be on the service release track then it will need to move to the feature release track to be able to implement the bug fix and benefit from the system upgrade. This process can be very risky in a production environment and should be done with caution, planning and thorough testing.

Before any upgrade, please consider the points below to ensure that the upgrade is done successfully and that you are prepared to restore the server into its previous state anytime if the upgrade is not successful or causes unexpected problems:

1. Backup all your Qlik applications on the server and move them into a separate drive or folder
2. Backup all the config files and folders from within the Qlik installation folder such as: %ProgramData%\QlikTech  Or  %ProgramData%\Qlik\Sense
3. Make sure that you have a test or development environment that is an exact image of the production environment.
4. Perform all the windows operating system updates.
5. Totally uninstall the product in the test environment, remove all unnecessary folders mentioned above and then perform a clean installation.
6. Copy and import 2 or 3 of your most sophisticated applications back to the server after the upgrade and make sure that the applications are running successfully.
7. If the applications prove to be running fine, make sure that the calculations are accurate and the visualisations are displaying the same was as in the previous version. 
8. Check that the system users and permissions are in place.
9. Check that the system licenses are re-created and tokens allocated if needed.

Once the above points are done, you will be ready to perform the same upgrade on the production server during a scheduled down time.

Related links:

https://help.qlik.com/en-US/qlikview/12.1/Subsystems/Server/Content/QlikView%20Server/QVSRM_Upgrade.htm
https://help.qlik.com/en-US/sense/1.1/Subsystems/Installation/Content/InstallationLicensing/Upgrading.htm