The course is in 6 sections, so I'll separate them by parts. I do have Windows Server experience, and 2019 is new to me, though the general idea is the same. The first relevant video opens with " I was speaking recently with a network administrator for a global company. He told me that his IT infrastructure was out of date because his Windows Servers were a version or two behind the newest thing from Microsoft." Just because you can upgrade doesn't mean you should! If your stuff works (well), it works. If new features help your business, or have the possibility for your business to 'grow' into them then sure, upgrade. But there's no need to keep up with the Jones or Gates.