Kindle Touch Notice Folders Breaking My App

[SteveEisenberg]

A helpful user reports that my KinCleaner freeware program to automatically archive or delete Kindle notices, originally tested on the Kindle Keyboard 3G, fails on his WiFi-only Kindle Touch when used to clear Overdrive public library return notices.

One reason is that the file name structure for library return notices changed with the newer Kindle model.

Here's an example of a US public library return notice from the documents folder of my Kindle Keyboard 3G:

Personal letter-asin_LoanExpired_B001D23SVM-type_PSNL-v_0.azw

And here is an example, provided by my helpful user, from the documents folder of a Kindle Touch:

Personal letter_LoanExpired_B0036VO4BG.azw

If that was the only difference, I would come up with a rule that applies to both devices (archive if file name starts with "Personal", contains "_LoanExpired_", and has the extension .awz).

However, there is a bigger difference with the Touch. In addition to the notice file, the Touch has new notice subfolders inside the documents folder. Despite the file-appearing extension, this is a sample folder name:

Personal letter_LoanExpired_B0036VO4BG.sdr

So, my questions are:

-- What is the purpose of the new subfolders? Do they ever have meaningful contents? And what are the implications of deleting them?

-- Is the new Overdrive notice structure for the Touch matched by comparable changes for other notice types? For reference, here are examples of waiting for delivery and charges exceeded notices from the Kindle Keyboard 3G:

17 Personal Documents waiting fo-asin_A2GTPRZFS20ICL-wifi-waiting-type_PDOC-v_0.azw

Personal Document Charge exceede-asin_2GCSNM2H5VFRPJLQSB544RNOZOOPJUCC-129030843-NOTE-type_PDOC-v_0.azw

-- If you delete one of the new subfolders from code, and the user then wants to restore the notice from a backup folder I keep on the PC, could a newer notice with exactly the same name have come back onto the device?

Lastly, although I've tried to keep KinCleaner as free a project for me as it is for my users, I may need to buy an actual newer device to test this stuff. But i'd only do it if confident that I would only have to buy one more device, this year, to make my app current. Is the notice structure the same for the Touch 3G and plain new Kindle as it is for the Touch WiFi-only?

I'm guessing the Fire to be so different that a tablet notice deleter would be a whole other project and/or that Fire users get few annoying notices. True?

The great majority of unneeded notices I get are 3G-specific. So I'm interested in WiFi-only models only to the extent to which they mirror 3G models. I think their notices (WiFi-only models vs. 3G) are formatted the same, but is that correct?

Thank for all input.