Have you ever needed to switch from one content management system to another? Maybe you were moving from something closed-source to something open source. Maybe moving from something older to something fancy and new? Maybe from something traditional like WordPress to one of those cool new "Headless CMSs."

Whatever the reason, there's always things that go great and things that go... unexpectedly.

What are you best and worst stories from migrating a site from one CMS to another? What bugs did you find? Did you redesign at the same time? Were your editors scared or excited?