Hello, sorry to revive an old thread. I'm getting the "Some data in My Library could not be downloaded. It may have been saved with a newer version of Zotero." error each time the iOS version of Zotero tries to sync. I have another version of Zotero on my laptop (Windows) and it seems to sync without issue.

On iOS, I turned on logging and sent in a log with ID: D1586459660. There are apparently 51 sync issues.

Edit:
Ah, just noticed this thread was for V5 of Zotero. I'm running V1.0.3 Build 5 on iOS and 6.0.13 on Windows. I also have V6.0.13 running on MacOS but both the Windows and Mac versions are syncing fine... just iOS is throwing errors.

Ah ok, yep I see the pdf file. I did import a large number of items from Mendeley Desktop.

If I open that pdf in the built-in Zotero pdf reader on my Windows laptop, I don't actually see any of the highlights; however, in the "Show Annotations" sidebar, I do see all the text that was highlighted. If I click on the annotation from that sidebar, it does put a dashed blue line around the correct text in the main pdf. So Zotero seems to understand that the highlights were there.

If I head over to Mendeley Desktop, the highlights are just the default "yellow" colour.

Edit:
I should add that I was using Mendeley Desktop V1.19.8 if that matters.

Edit 2:
If I open the same pdf on my iOS device, I do NOT see any of the highlights and I do NOT see the annotations.

We've corrected the annotations in your online library with a missing color value. You should now be able to sync the annotations to iOS. The annotations will still look incorrect for now in the desktop app, but we'll add a repair step for these in the next version.

(This seems to be a bug with imported Mendeley libraries where an explicit color sometimes wasn't set. We'll fix this more generally for other users soon.)

Hi @dstillman, I am having the same problem EmnaX had. I also have imported Mendeley annotations.
I am running 6.0.26 on MacOS and 1.0.13 Build 3 on iOS.

Thank you so much, @dstillman!