> LGPL does require that you provide users the ability to link against a modified version of the LGPL library.

That's correct for LGPLv3, but I believe LGPLv2 is more nuanced.

With LGPLv2, I don't think it requires that you provide the ability. It has to be possible if you get access to the executable (which may require that you jailbreak your device, for instance). For instance, it is my opinion (not legal advice) that it is fine to use an LGPLv2 Java library in a proprietary Android app, because you can technically go replace the class files corresponding to the LGPLv2 library in your apk. It's not easy to do (unlike swapping a dynamic library), but it is possible.

On iOS things are even shadier, since iOS didn't allow apps to use the dynamic linker until iOS 8(?), and you have to pay Apple $100 for the priviledge of deploying the resulting app on your own device...

> can technically go replace the class files corresponding to the LGPLv2 library in your apk

APKs in the Android app store MUST be cryptographically signed. So, it is impossible.

The only practical solution that an LGPL license provides for Android apps is to fall back to the viral GPL license.

But you don't have to publish that modified apk to Play Store. You can just sign it with your own key and install the apk manually, no root needed.

I know there are some apps that do its own cryptographic signature verification on their own, but most apps don't do that, so replacing a LGPL library in an APK is actually feasible in most cases. It is not hard to do so either.

They must be signed to be on the store, but I don't think it's impossible to run unsigned apks on the device (maybe you need the developer mode, though).

But even then, wouldn't that count like tivoization? LGPLv3 says you need to provide instructions to replace the lib, but LGPLv2 does not. Couldn't I say "I honor the LGPLv2, because it would be technically possible to update the library, but unfortunately for you it is behind some tivoization that you would need to break first"?