You mentioned that you upgraded to 7.6.0, but your screenshot is using the old 7.5.x style. Did you intentionally roll back certain files to their 7.5.x versions? If not, you may want to check that you did a complete install/upgrade, and that your files are all 7.6.0 versions.

Check the file dates in the package, with those of your production forums, and confirm that you didnt miss any.

Current developer of UBB.threads PHP Forum Software // 7.7.3 released!
isaac @ // my forum @