Two important specifications (for me) for annotations: 1. Long term preservation (most important): I want to use the annotations in 10 years, 30 years, etc. Us

Two important specifications (for me) for annotations: 1. Long term preservation (most important): I want to use the annotations in 10 years, 30 years, etc. Using them means they must be readable and be connected to the object they annotate. 2. Migration through updates to the object. That is, if I annotate a PDF of a book, and later a new revision or edition comes out, I'd like my notes to automatically transfer. I know there are some cases where that is difficult - e.g., if the annotated object isn't present in the revision - but most notes can be migrated. I don't know anything that does #2. #1 is only available in PDFs (and especially PDF/A), afaik.