title_body: How to adapt annotations from an old edition book to a new edition book? I like to write notes on ebooks for reorganizing the topics and for helping with my understanding. 
  
  One question which I have with this way is that: when a newer edition of the same book comes out, what should I do to migrate the notes that I wrote for the old edition to the new edition?
  
  More specifically, my ebooks are all pdf files. 
  
  
  A book in an old edition and in a new edition are two different pdf files.
  I have written my notes in the form of editable annotations on the pdf files. By annotations, I mean, for example, text comments, underlines, shapes that single out parts of the text, arrows that connect different parts of the text, ....
  
  
  Here are some ways that I can think of:
  
  
  Find some way to export the annotations from the old edition of a book, and then import them to the new edition of the book. The problem with this way is that there is likely to be a problem of mismatching positions of the annotations in the new edition.
  Copy the annotations of the old edition of a book into a plain text file, and rewrite them to make them less independent on specific edition of the book. When reading the new edition, add or modify the notes in the plain text file accordingly. The problem with this way is that the work to copy the annotations from the old edition into the plain text file may be huge.
  Leave the annotations on the old edition of the book, and when reading the new edition of the book, consulting the annotations on the old edition, and making new annotations on the new edition.
  The problem with this way is that reading several editions of the book at the same time is cumbersome. 
  
  
  What are your suggestions?
upvoted_answer: This is a very interesting question, and I did some preliminary research on it. 
  
  The basic problem here is that PDFs are generally  not considered to be an editable document and that most annotation solutions are specific to one software platform. 
  
  Because PDFs are considered to be more as output than an editable document, versioning hasn't really been implemented for the annotations. 
  
  I am not particularly well-versed in the Adobe platform, but I know that some mobile PDFs readers let you export annotations to a text file. (Several can do this). 
  
  Some other options are to do the annotations and versioning in MS Word and/or Google Docs instead of PDF. Those are both good for storing annotations and keeping track of versions. Also, both software have all sorts of mobile apps and syncing solutions. 
  
  Here's an interesting thing. If your file is an epub and if you have uploaded it to Google Play Books (GPB), then when you annotate the epub file, the annotations will be stored in a (versioned) Google Docs file for your account.  (Here's what one of my files looks like: https://docs.google.com/document/d/1FvqqixSaZoY04Ua2L6wTK1mHmU5UptYISZ4z4oFSd1I/edit?usp=sharing ) 
  
  Another possibility is to search through the available plugins for Google Docs or MS Word to see if there are plugins (free or commercial) which let you version comments better. 
  
  I realize that this is not the solution you want, but those are the solutions I am aware of.