[kokaros]

Thanks for the prompt replies guys.

Originally Posted by NiLuJe

Whispersync has nothing to do with KOReader, so I'm not sure what you were asking there...

Yes, I am aware that Whispersync has nothing to do with KOReader. The answer I was looking for there is the one you gave me here:

Originally Posted by NiLuJe

KOReader's sync feature can sync *progress*, but not notes/higlihts (AFAIK, I'm not familiar with the details).

Also, thank you for letting me know about this:

Originally Posted by NiLuJe

KOReader's own metadata handling is put in the book's sidecar folder (e.g., for an ePub: ${filename}.sdr/metadata.epub.lua). The actual content of the file is portable, it doesn't depend on a specific filename, so you can move stuff around manually without any issue.

I had no idea KOReader was creating locally a .sdr folder, just like Kindle's native reader does, containing the book's highlights and notes.
Having read your replies, I still have a few more questions. Please bear with me

FIRST:
Going back to point 3) of my post:

Originally Posted by kokaros

3)Would allow me to backup/export my highlights and notes in a format which would be importable on:

a)the same book on other e-reader devices
b)the same book on the same device, e.g. in case I decide to delete the book and its contents and re-import it along with its highlights and notes at a later point

I can see how I can backup the highlights and notes (the .sdr folder) on my PC as NiLuJe explained, and have the ability to import them again on the same kindle, so point b) is covered (I've just tested this). How about point a)? Does KOReader use the same format for the folder .sdr and contained files .lua across other e-reader devices? I.e. if I put the exact same ebook on another device which uses KOReader, can I just copy the .sdr folder and be sure that my highlights and notes will appear there as well?

SECOND:

Originally Posted by ilovejedd

In addition to human-readable exports, it's also capable of merging highlights created on multiple devices in native KOReader format.

I've already downloaded and played around with the KoHighlights program. I've noticed the "Merge/Sync" option in the top bar menu. When you hover over it, you get the following message:
"Merge the highlights from the same book in two different devices, and/or sync their reading position. Activated only if two entries of the same book are selected."

What does it mean with that last sentence "Activated only if two entries of the same book are selected."? Do I need to have 2 separate e-reader devices plugged in at the same time, with both of them having the same book stored on them to have the "two entries of the same book" appear within the program, so that in turn this feature works?

THIRD:
Does Amazon's Whispersync sync:

a) the book file itself
b) the book's highlights
c) the book's notes

across other kindle devices owned by me? I.e. if I were to buy a new Kindle and register it with the same account as the one I am using on my current one, will I get a copy of the things I've listed above on my new kindle?

FOURTH:
If the answer to my THIRD question is yes, does this apply to books I've transferred to my original Kindle through USB, or is it just for books that were transferred to it via the "Send to Kindle" software or bought through Amazon's store?

FIFTH:
Do we have any confirmed successful downgrade attempts of FW v5.12.4 running on Kindle PW3 here on the forum?

SIXTH:
Even if we don't have any confirmed successful downgrades, what can I do prior to a downgrade attempt, to be 100% sure that if my device gets bricked I'll be able to easily unbrick it?

SEVENTH:
What FW version would you recommend downgrading to, so that I can be 100% sure that even with WiFi turned on I won't get a forced OTA update?
Having the JB without being able to connect to the WiFi is pretty lame

I hope this post isn't too overwhelming