How to download old version of K4PC

[tom-huntington]

Grok said

For 2.8.0 (70980): http://download.epubor.com/KindleForPC-installer-2.8.70980.exe
(Hosted by Epubor, a common spot for Kindle version archives; release ~Sep 2025)
For 2.8.2 (70987): http://download.epubor.com/KindleForPC-installer-2.8.70987.exe
(Also from Epubor; release ~Feb 2026)
The latest in the series (2.8.3 / 70995): https://kindleforpc.s3.amazonaws.com/70995/KindleForPC-installer-2.8.70995.exe
(Direct Amazon S3 link, matching your partial URL pattern)

It seems like if you know the version number, then the official amazon url is

str.format('https://kindleforpc.s3.amazonaws.com/{0}/KindleForPC-installer-2.8.{0}.exe', 70987)

[Satsuoni]

I mean, yes? It is well enough known, except that the number also goes up sometimes, so eventually it will be 'https://kindleforpc.s3.amazonaws.com/{0}/KindleForPC-installer-2.9.{0}.exe'.format(build_number), etc.
2.8.0: https://kindleforpc.s3.amazonaws.com/70980/KindleForPC-installer-2.8.70980.exe
2.8.1: https://kindleforpc.s3.amazonaws.com/70985/KindleForPC-installer-2.8.70985.exe
2.8.2: https://kindleforpc.s3.amazonaws.com/70987/KindleForPC-installer-2.8.70987.exe
2.8.3: https://kindleforpc.s3.amazonaws.com/70995/KindleForPC-installer-2.8.70995.exe
2.9.0: https://kindleforpc.s3.amazonaws.com/71000/KindleForPC-installer-2.9.71000.exe

These are supported versions for the moment for KFXArchiver. One can extract them with 7zip and point archiver to the folder with 4th (optional) argument if one does not want to install other k4PC version. (That is mostly debug functionality, one still needs to have Kindle storage filled with DSN/secret)

[Satsuoni]

Interestingly, today, 20206.03.29, those links give me access denied, and that includes official download page of Amazon.

[tomsem]

For some reason I'm not able to install 2.8.3. Installer fails to launch Kindle app (it runs as a background process for a little while but then quits). I used the download link on amazon.com, which seems to be same as above.

I had 2.8.0 working previously but wanted to update to a more current release. I reinstalled 2.8.0 and signed in, disabled automatic update.

When I exited and launched app, of course, it wanted to update to 2.8.3. I let it do that but again the app fails to launch.

So I guess it's back to 2.8.0.

FWIW, this is Windows 11 Pro (ARM) running virtualized in UTM on MacBook Pro, and it's basically just to run the Kindle app and the KFXArchiver tool when I need to. I import kfx-zip to calibre on a non-virtualized Windows 11 Pro system, with K4PC 2.4 on there (which works for everything except more recently published titles).

[Satsuoni]

I am entirely unsure how that is supposed to run on ARM at all, given that those are x86 executables (not x64 even). I guess a compatibility layer? Or do you emulate x64 windows? Well. Either way, Amazon is dropping this K4PC completely soon.

[29988122]

I am entirely unsure how that is supposed to run on ARM at all, given that those are x86 executables (not x64 even). I guess a compatibility layer? Or do you emulate x64 windows? Well. Either way, Amazon is dropping this K4PC completely soon.

I can't help but wonder, what's the plan next for us to deDRM in a relatively smooth workflow?

I mean I myself did some tinkering with android apk static analysis(not drm related), and claudecode/codex are doing exceptionally on this matter. I've heard that with frida mcp it's working the same level doing run time dynamic analysis.
I guess extracting keys from eink devices/android will still be relatively trivial in the foreseeable future.

====

However, 2.8.2 is already not working for me currently (unable to connect/sync). I have to download 2.9 to make it even want to pop out the login webview window, to connect to the server/gain the key.
Thanks to your hardwork, archiver binary still works and extracted the book correctly. The k4i key did not work though, as you've emphasised in the utility verbose.

Do you think when amzn cut all the connection of old kindle pc client(move to windows store client UWP for example), what kind of workflow can we try to reestablish, or the cat-mouse game will ever be over or not?

Thanks for your hardwork Satsuoni - without your very hard dev effort these days, I wouldn't be able to translate my legally purchased kindle books into my mothertongue via LLMs.

Thanks again!

[Satsuoni]

I can't help but wonder, what's the plan next for us to deDRM in a relatively smooth workflow?

I do not know? I never worked with UWP apps, so maybe windows would have to be switched to developer mode or something? No idea. For Mac, as I mentioned, SIP needs to be disabled so that the keychain entry with DSN/secret would be accessible, or.. well, there are other ways, none easy.

I mean I myself did some tinkering with android apk static analysis(not drm related), and claudecode/codex are doing exceptionally on this matter. I've heard that with frida mcp it's working the same level doing run time dynamic analysis. I guess extracting keys from eink devices/android will still be relatively trivial in the foreseeable future.

Yes, AI is, somewhat regrettably, better at it than I am. Sadly, I am not proficient in AI use (and yes, that requires skill, just a different skill from what I have. Closer to human skills, in a way). I wonder if it can be used to (reliably) deobfuscate what they did to source code...

That said, yes, even my Frida script still works for android (emulator), one book at a time... (then it crashes). There are other ways, I assume, but would need android native executable.

However, 2.8.2 is already not working for me currently (unable to connect/sync). I have to download 2.9 to make it even want to pop out the login webview window, to connect to the server/gain the key. Thanks to your hardwork, archiver binary still works and extracted the book correctly. The k4i key did not work though, as you've emphasised in the utility verbose.

That is a bit odd, so quickly... ah well.

Do you think when amzn cut all the connection of old kindle pc client(move to windows store client UWP for example), what kind of workflow can we try to reestablish, or the cat-mouse game will ever be over or not?

Sideload UWP and hope that it is actually sandboxed and not allowed free reign to verify random stuff?
We'll see.

Thanks for your hardwork Satsuoni - without your very hard dev effort these days, I wouldn't be able to translate my legally purchased kindle books into my mothertongue via LLMs.

Thanks again!

You are welcome.