Paul HittandClaude Opus 4.8
31551f60f2
Nothing updates this app on its own. It is downloaded as an APK from a web page, so there is no store to notice a release and no background updater to install one — a person can run a build from months ago indefinitely, through every fix that came after it, and never find out. That is the part of sideloading that is genuinely worse than a store, and this is the only thing that closes it. The background check asks the RELAY the install is signed in to, not a fixed address of ours. Pointing every install at flamenetmessenger.com would mean an app whose whole claim is that it does not phone home checking in with us on a timer, from every device, including the self-hosted ones that deliberately never contact us at all. A relay that publishes no manifest simply produces no prompt. "Check for updates" in Account is the other half, and the reason the fallback to our site exists: pressing it is a question the user asked, so answering "your relay does not publish updates" when we plainly could is unhelpful. It tries the relay first and names whichever host answered, so it is never a silent phone-home. It also distinguishes "no newer build" from "could not check" — reporting silence as good news is how somebody sits on a build with a fix in it believing otherwise. The download URL is built from the host that answered and never read from the manifest. A `url` field would let any relay send its users to an APK on a host of its choosing; Android's signature check is a backstop, not a reason to build the hole in front of it. A test asserts a hostile manifest cannot move it, and fails if the guard is removed. versionCode is bumped and `scripts/release-manifest.sh` reads it back out of the built APK, so the manifest and the artifact cannot drift. ⚠️ Nobody already installed sees this: every build before this one has no check in it, so the first prompt anybody gets is for the build after this one. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Flamenet Messenger — Android
The Android app, and the two libraries under it.
engine/ the protocol: X3DH, Double Ratchet, sealed sender, safety numbers,
key transparency. Plain Kotlin/JVM — no Android in it at all.
client/ the relay transport: HTTP, auth, the §8 routes.
app/ the Compose app.
interop/ the cross-engine driver; not shipped.
engine and client are deliberately plain JVM libraries. The protocol has
nothing to do with Android, and keeping it off the platform means their tests
run anywhere a JVM does — no SDK, no emulator, no device, which is also what
lets them gate in CI on Linux:
./gradlew :engine:test :client:test
The app's own unit tests need the Android SDK but still no emulator (Robolectric):
./gradlew :app:testDebugUnitTest
Where it stands
PARITY.md is the definition of done for this app — read that, not this. Every row there names the iOS file it came from so it can be re-checked rather than trusted. Headlines as of 2026-08-28: messaging, groups, attachments, voice notes, stories, calls, sealed sender, key transparency and the encrypted vault are built and tested; a cross-platform round trip against iOS was verified on 2026-08-26.
⚠️ This file said "Nothing here is an app yet" until 2026-08-28, above a tree containing the finished app — the README described the repository as it was when the engine landed and nothing updated it as the app grew around it. If a claim here ever disagrees with PARITY.md or with the tree, believe those, and fix this.
Why the engine came first, and is held to the vectors
An Android client needs the protocol implemented a third time, and the third
implementation is the one that finds the places where the specification says
less than the two existing engines quietly agreed on — but only if it is
written against the spec and the published vectors rather than against a
reading of our own Swift and JavaScript. So the engine is held to
test/vectors/protocol-v1.json in
flamenet-e2e — the same file the
other two engines are checked against, read from that repository rather than
copied here, because a copied vector file drifts and a drifting vector file
stops being a check. PublishedVectorsTest looks for it beside this checkout
and fails loudly if it cannot find it; FLAMENET_VECTORS overrides the search.
Two implementations that agree may both be wrong in the same way, especially when one was written while reading the other. The audit-path ordering in §19 is the worked example: a top-down reading of a bottom-up path produces the correct root for every left-spine index, so it passes any test that only checks index 0. The vector file pins a right-descending index for that reason, and the Kotlin tests assert both that the published path verifies and that the same path reversed does not.
If this engine ever disagrees with the file, the interesting question is which of the three is wrong — not this one by default.
Contributing and security
- CONTRIBUTING.md — building (JDK 21,
JAVA_HOMEis not optional on a Mac), the test gate, and the platform traps that cost an hour each. - PARITY.md — what iOS does, what this does, and what is left. It is the definition of done for this app.
- SECURITY.md — threat model and where to send a vulnerability report. Not an issue tracker matter: security@flamenetmessenger.com.