Version: (using KDE 4.2.1) I didn't find this info if the doc itself is modified or the annotations are kept as external file (something like diff).
From documentation addition done few days ago for KDE 4.2.2: " Okular allows you to review and annotate your documents. Annotations created in Okular are saved internally in the local data folder for each user. " I'd say this is ok.
Pino, thank you, however when comes to data integrity, it is more about focus on the file, not annotations, i.e. the statement: "The annotated file is not altered in any way". is more clear, and strict. From the statement as you posted still it there is no 100% guarantee some bit is not flipped in the viewed file. So if you could just add (not replace) this sentence or similar I would be grateful (of course if this is true ;-) ).