I have seen this mentioned a few times in the forums here, but I wanted to find out what Adobe plan to do to resolve the issue.
We currently make PDFs available to our customers, with password encryption that does allow commenting, etc.
Adding comments to the PDF on a laptop works fine. However, when we try on an iPhone or iPad, Acrobat says that the file is read-only.
Unless Adobe can fix this, we will have to tell our customers that they cannot add comments to the PDFs that they have obtained from us.
I hope you're doing good.
Per my understanding, this is a feature-related issue; you cannot access(edit or use any tools) encrypted files on the Acrobat reader mobile application. So, if you want to use and edit any encrypted file, you can only access it through the Acrobat desktop application.
I hope this helps.
Thanks for your reply.
Yes, that is also my understanding. I see it more as a feature limitation on the mobile app. I think Adobe do need to look at this again. We are going to have tell our customers that they can only add comments to our PDFs on a desktop or laptop, or use another PDF Reader. We have found other mobile apps that will open encrypted files and allow commenting.
Another post with the same issue has a comment from an Adobe employee, which confirms that this is a 'limitation' on the mobile app:
There are limitations between the desktop and mobile versions of the application. If the document has been protected, you won't be able to make changes to the mobile version.