Jira 8 contains the Atlassian Platform 5.0. This platform changed the autowire-mode from the deprecated 'auto-detect' to 'constructor'. As a result, older versions of Kantega Single Sign-on will not work at all on Jira 8 because core components relied on setter-injection.
Kantega Single Sign-on made neccesary changes to solve this in version 3.4.7.
If you are unlucky to upgrade to Jira 8 before upgrading Kantega Single Sign-on to 3.4.7 or newer, you will have run into a problem.
You will see something similar to this in the log:
java.lang.NullPointerException at org.kantega.atlaskerb.KerbConfManager.settings(KerbConfManager.java:493) [?:?] at org.kantega.atlaskerb.KerbConfManager.isPreemptiveAuthEnabled(KerbConfManager.java:197) [?:?] at org.kantega.atlaskerb.AtlasKerberosFilter.isMappedRequest(AtlasKerberosFilter.java:342) [?:?] at org.kantega.atlaskerb.AtlasKerberosFilter.doFilter(AtlasKerberosFilter.java:93) [?:?] at
And you will also experience that you are not able to log into Jira.
Best is if you upgrade Kantega Single Sign-on to 3.4.7 or newer before you upgrade Jira 8.
If you did upgrade to Jira 8 and has no easy way to roll back, you will have to remove Kantega Single Sign-on jar file to start up successfully.
Removal is done by:
After the removal, please restart Jira 8 and install Kantega Single Sign-on latest version. You will keep config after reinstalling.
See also details from Atlassian on how to uninstall apps:
Please reach out to our support team if you struggle with your upgrade.