If you use Scrivener on both a desktop machine and on iOS, there’s an incompatibility between iOS 12 and Scrivener iOS you should be aware of.
The incompatibility regards images inserted as links via your desktop Scrivener. If you edit a document containing such an image link in Scrivener iOS, the image link will be erased.
It’s impossible to create such a linked image in Scrivener iOS, so this warning applies only to images created via desktop links. Here’s a link to the Scrivener Forums thread in which this is discussed in detail:
It’s on the list for the next Scrivener iOS revision, but that may not happen for a few weeks, as the developer (who is responsible both for Scrivener Mac and Scrivener iOS) is swamped. In the meantime, I suggest you turn on the following in your Scrivener Preferences (or Options, if you’re on Windows):
Scrivener > Preferences > Sharing > Sync > Mobile Sync “Take snapshots before updating documents.”
If you turn this on, Scrivener will preserve a pre-Dropbox sync copy of any document you edit on iOS. Should you lose an image link, simply drag and drop the image link from the snapshot back into its rightful place in your edited document. If you don’t use Dropbox (you might instead use iTunes, AirDrop, or some other iOS file utility) then I suggest you make a backup or take snapshots manually before you incorporate any iOS edits into your desktop project version.