Hey @samtsejerome, what SDK version are you trying to upgrade to? Either way, to get you unblocked it might be worth creating a new project and migrating your project files over the new project.
Another thing to try is clearing all your caches. If that doesn’t work, trying adding your project dependencies one by one to try and figure out what could be causing the yarnpkg error (as it seems it’s a rather rare occurrence among Expo users as there have only been a handful of reports of it).