Hi. Sorry WriteRoom for iOS has been discontinued for a number of years and won’t be updated for iOS 11. If you’ve been syncing your files to Dropbox you should be able to fairly easily transfer them to another app. If you haven’t been syncing to Dropbox there are third party apps that will allow you to browser your iOS device filesystem from your Mac to copy the files. The first google hit I get is: Browse and transfer iPhone files and folders