Noticed when playing both with mystic item's 2.0.6 both me and my friend get errors when playing together about a mystic sword-mysticitems 2.0.5 and 2.0.4 not compatible, but both of us run 2.0.6 in our mod files.  If this is an issue for anyone else it would be helpful for a fix, we both love playing with mystic items.

Try this:

• Open your mod manager's settings
• Select "Browse profile folder"
• Open the "BepInEx" folder
• Delete the "cache" folder

Figured out why this happens. Shouldn't happen anymore starting from 2.0.13!