[Ipe-announce] Ipe files getting corrupted on Mac OS X

[Otfried Cheong]

Recently two Ipe users mailed me PDF files that were originally created 
by Ipe, but that Ipe would no longer open with the error message "The 
document was created by a newer version of Ipe".

In both cases it turned out that the file they tried to read me was 
created by "Mac OS X 10.?? Quartz PDFContext" and not by Ipe.  I am not 
sure what happened, but apparently they had been previewing the PDF 
document, and the previewer took the liberty to overwrite the original file.

Ipe PDF files contain Ipe markup hidden inside the PDF structure.  When 
the file is modified by any other tool, this markup is lost, and Ipe 
will no longer be able to read it.  The error message ("newer version of 
Ipe") is a bug - I will fix this in the next version.

There is no way to recover the lost markup - you will need to go and 
search for a version that was not compromised by Mac OS X Quartz PDFContext.

So please be careful with PDF viewers that have the capability to 
overwrite the file being viewed, in particular on recent version of Mac 
OS X.

Cheers,
  Otfried