...
- https://my.atlassian.com/products/index
- https://www.atlassian.com/software/confluence/download-archives
- https://confluence.atlassian.com/confkb/after-upgrading-confluence-shows-error-occurred-during-template-rendering-contact-your-administrator-for-assistance-error-1283491784.html
How to resolve?
This issue is resolved to delete some data records based on the guide at
What I did was
- delete records based on the above guide before upgrading confluence
- upgrde
I hope this helps for others.