Tomorrow (July 2) at 5pm, during our regular weekly maintenance window, Libraries IT will be upgrading the software that powers the Library Wiki and IT Help. The new software provides a cleaner design, but functionality and layout remain pretty much the same. One change is worthy of note for page editors–the Preview option in Edit mode no longer has its own button. You will need to select Preview from the three-dot menu button:

If you have any issues getting into or using the Library Wiki, please visit How to Use the Library Wiki or submit a Hub ticket.