I have a similar problem, I removed all the old files Plugins folder and the entire InAppBrowser folder from the project. Then I import the updated 2.0.0 version from the Asset Store and I get below error in Xcode:
error: Build input file cannot be found: ‘/Users/tdpl/Documents/BuildsIphone/SooperpopTest/Libraries/Plugins/iOS/iOSInAppBrowser.mm’ (in target ‘Unity-iPhone’ from project ‘Unity-iPhone’)
Now, iOSInAppBrowser.mm file was there in the plugins/iOS folder along with below files
I deleted all of them before importing the version 2.0.0 and now the iOS folder just contains InAppWebBrowser.a file in Plugins/iOS folder.
Now when I keep all the above files and build with the latest 2.0.0 version, I get 26 duplicate symbols error.
What am I missing here? Could you please tell me what files to delete and what to keep while upgrading to 2.0.0?