[Android] Allow APK downgrades

[davidhedlund]

Is there an existing issue for this?

• This is a bug in RetroArch frontend
• I have searched the existing issues

Description

It is not possible to downgrade RetroArch to an older version.

Expected behavior

Expected behavior is that installing a stable or older version over a nightly build (or a newer stable version over an older stable one) either succeeds or gracefully handles the VersionCode mismatch without blocking installation errors.

Steps to reproduce the bug

Scenario A (Nightly to Stable)

• Install the latest nightly build from the [Libretro Nightly Buildbot](https://buildbot.libretro.com/nightly/android/).
• Attempt to "downgrade" by installing the latest stable release from the [Libretro Stable Buildbot](https://buildbot.libretro.com/stable/).
• Observe the Android package manager prompt:

RetroArch

Do you want to update this app?
[Cancel] [Update]

• Select [Update].

RetroArch
App not installed as package appears to be invalid.

[Done]

Scenario B (Stable to Older Stable)

• Install a newer stable release (e.g., v1.22.2).
• Attempt to downgrade to a previous version (e.g., v1.22.1).
• Observe the Android package manager prompt:

RetroArch

Do you want to update this app?
[Cancel] [Update]

RetroArch
App not installed as package appears to be invalid.

[Done]

• Select [Update].

Scenario C (Nightly to Stable Via Obtainium)

• Open Obtainium on Android.
• Click + Add, select Crowdsourced app configurations, click Browse all apps, and search for RetroArch (or visit Obtainium Apps Catalog).
• Install a Nightly build (e.g., RetroArch, RetroArch (AArch64), or RetroArch (32-bit)).
• Attempt to downgrade the installation by switching to or installing a Stable version.

Some errors occurred

Cannot install an older version of an app (VersionCode 1785633370 → 1763607214)
[RetroArch]

[Okay]

Version/Commit

1.22.2

Bisect Results

No response

Present in the nightly version

Yes, this is reproduced in the nightly build

Platform & operating system

Android

Affected Cores

No response

Environment information

No response

Relevant log output

[davidhedlund]

As of Android 17 and earlier, generally it is not possible to downgrade an APK directly over an existing installation without uninstalling the app first or bypassing system restrictions.