Ok so I'm thinking about upgrading to a SLX drivetrain, and I currently have a Shimano Deore Xt 2x10 on my Devinci Troy. The question is whether it is even worth it cause the cassette may be too wide for my chain/seat stay triangle. Definitely need the upgrade as I do enduro riding and the 2x10 is a hassle. Never done this before. I can also just get a new chainring up front and a bigger range 10 cog cassette in the back, but I would like to go to something a lot nicer.
With 11 speed cassettes the compatibility issue is not the width of the dropouts or rear hub, it's will the cassette fit on the freehub body. Some 11 speed systems require a slightly longer freehub body to fit onto.
Shimano MTB 11 speed cassettes will fit onto the same freehub body as a 10 speed (which is actually the Shimano 'Hyperglide' freehub standard that has been in use for decades). It manages this by having closer sprocket spacing and overhanging the back of the freehub body somewhat. The overhang is possible because the large low gear sprockets required on 11 speed systems can clear the spokes.