The two versions of top and left navigation theme have been disabled for, because they do not work properly in confluence 2.8.2.
Spaces using these should fallback to the default theme.
Sorry for the 1 inconvenience.
If you are using Approvals Workflow Theme in your space, please go to space admin, themes and select Default Theme (2.8.x), Approvals Workflow Plugin ready.
Confluence core has been upgraded to version 2.8.2 More info on changes, fixes and new features can be found
If anything broke, please send email to firstname.lastname@example.org.