While Apple's MacOS High Sierra has gotten good reviews, Adobe Illustrator and InDesign users should hold off on getting the new OS for a bit.
It's usually a good bet to check whether your current apps are compatible before upgrading/updating your OS, but the Adobe Illustrator and InDesign issues are bad enough that designers who rely on those two apps should (really) wait awhile.
How bad is it? Apparently with Illustrator, the app is having problems launching, opening files and creating documents as well as a myriad of other issues including brushes rendering, colour management and other errors. Upgrading to the Apple File System breaks a lot of functions - there's no workaround for problems caused by it so far.
As for Adobe InDesign, the cursor shows up as a pixelated box - an annoying problem with no fix so far.
Adobe is aware of the issues customers are facing and is working on an update to fix it. In other words, Illustrator and InDesign are just not High Sierra compatible for the moment. The update will happen but until it does, designers/graphics professionals should stick to older versions of the MacOS and avoid buying new machines that come preloaded with High Sierra for the moment. Hopefully your trusty old machine should still be able to hold the line, for now.