Failed cluster upgrade from 7.19.4 to 8.5.11

[a_abdelrahman_space_gov_ae]

Dear all,

We were trying to upgrade 2-node cluster from 7.19 to 8.5.11. However, after completing the upgrade, the application is not openning on both nodes and showing the error message:

BootstrapException: Unable to bootstrap application: Exception bootstrapping cluster:Cannot perform rolling upgrade from 7.19.4 to this version (8.5.11). This version of Confluence can only be rolling-upgraded from a cluster running a version between 8.4.0 and 8.5.11.

Please note that we were planning initially an upgrade without down time, so we have enabled rolling upgrade on the cluster, but since the upgrade from 7.19 to 8.5 requires down time, we continued with the upgrade instructions on this page https://confluence.atlassian.com/doc/upgrading-confluence-data-center-1507377.html. However, rolling upgrade was not disabled prior to this activity.

can we now fix this error, or do we need to reinstall the original version?? Please advise as i don't have extensive experience in this product. 

[Rilwan Ahmed]

Dear @a_abdelrahman_space_gov_ae ,

Welcome to the community !!

Now that you have completed the upgrade process, I suggest to stop confluence in all instances and start confluence only in one node and see if it works. If not, I suggest you to contact Atlassian support directly for the solution in https://support.atlassian.com/contact/#/