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What's new in bitchat for Android (github version) 2.1.0

Bitchat Android v2.1.0

Highlights

Spam filtering for public mesh and geohash chats, enabled by default. Phone users can disable it in settings.
More reliable geohash participant lists, nicknames and blocking, including removal of blocked users' messages.
Corrected Cashu ecash amount formatting for fiat-denominated tokens.
Clearer light-mode voice-note waveforms, improved onboarding layouts and consistent QR scan controls.
Basque language support and spam-filter translations.
Improved incoming-message autoscroll and verification-sheet layering.
QR scanner initialization fixes for minified releases, plus concurrency fixes for security-cache cleanup and relay snapshots.
Panic reset confirmation and accurate reporting of wipe outcomes.
Wear OS: swipe right from chat for the app menu, including a confirmed Quit action.
Privacy and security hardening: exclude app data from backup/device transfer, validate message fragments and encoded data, check verification QR timestamps, and limit APK downloads and decoded packet sizes.
Prevent recipient-less Nostr private-message envelopes from exposing a stable mesh identity.
Updated bundled Nostr relays.

Versions and downloads

Phone 2.1.0 (41) requires Android 8.0/API 26 or newer. Wear OS 0.1.6 (1000000007) requires API 33 or newer. Both use com.bitchat.droid and target API 37, from commit b8016545e00cc7317fd9dc938b8cb7796db190ff.

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bitchat-android-arm64.apk: most modern Android phones.
bitchat-android-universal.apk: compatibility fallback.
bitchat-android-x86_64.apk: x86_64 devices and emulators.
bitchat-android-wear.apk: direct Wear OS installation.
bitchat-android-play-upload.aab: signed phone bundle for Play.
bitchat-android-wear-play-upload.aab: signed Wear OS bundle for its separate Play track.

Only signed binaries and reproducibility metadata are attached. No unsigned APKs or AABs are published.

Reproducible-build verification

Requirements: Git, Docker (at least 16 GiB memory), and GitHub CLI.

git clone github.com/permissionlesstech/bitchat-android.git cd bitchat-android git checkout v2.1.0 tools/reproducible-builds/build-in-container.sh .reproducible-build/verify-2.1.0 gh release download v2.1.0 --repo permissionlesstech/bitchat-android    --pattern BITCHAT_BUILDINFO.json --pattern BITCHAT_SHA256SUMS.unsigned    --dir .reproducible-build/metadata-2.1.0 gh attestation verify .reproducible-build/metadata-2.1.0/BITCHAT_BUILDINFO.json    --repo permissionlesstech/bitchat-android gh attestation verify .reproducible-build/metadata-2.1.0/BITCHAT_SHA256SUMS.unsigned    --repo permissionlesstech/bitchat-android cmp .reproducible-build/verify-2.1.0/SHA256SUMS.unsigned    .reproducible-build/metadata-2.1.0/BITCHAT_SHA256SUMS.unsigned

To check downloaded release-file integrity:

gh release download v2.1.0 --repo permissionlesstech/bitchat-android --dir release-files (cd release-files && shasum -a 256 -c BITCHAT_SHA256SUMS)

Signing certificates (SHA-256)

GitHub APKs and Play upload: 3b03fa66a5451321100792f5b55a7b4966d5c8dc10c6daa40aa95ea489531bca
Google Play app signing: 5e651dd0c80d1f57f2617964955085e28949dd04addac7b53fe9d2f11e172aa2

Google Play signs delivered APKs separately; their bytes need not match the GitHub APKs.

Validation scope

Phone unit tests: 762 passed, 3 existing skips. Wear unit tests: 238 passed. Contract tests and two synthetic minified-scanner runtime tests passed. Two independent local canonical builds matched byte-for-byte.

Both independent builds in the tagged release workflow also matched byte-for-byte. All eight canonical binaries and both public build-metadata subjects passed GitHub provenance verification against the exact tag, source commit and release workflow. APK signing is deterministic; existing signing-certificate continuity and signed AAB payload comparisons passed.

Existing lint findings remain; the six targeted translation errors were fixed. Changed-line coverage is unavailable because its Gradle task is not wired. Physical-device, cross-client/endurance and Play-delivered upgrade tests were not completed for this release; these gates were explicitly waived. This is not a claim that those checks passed.

Full changelog

Changes since v2.0.3

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About bitchat for Android (github version) 2.1.0

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bitchat for Android

A decentralized peer-to-peer messaging app with dual transport architecture: local Bluetooth mesh networks for offline communication and internet-based Nostr protocol for global reach. No accounts, no phone numbers, no central servers.

This is the Android implementation of bitchat, fully protocol-compatible with the iOS version for cross-platform mesh communication.

bitchat.free

GitHub Releases

See it in action

Offline mesh conversation	Geohash globe picker

License

This project is released into the public domain. See the LICENSE file for details.

Features

Dual Transport Architecture: Bluetooth LE mesh for offline messaging, Nostr relays for internet-based messaging
Location-Based Channels: Geographic chat rooms using geohash coordinates over Nostr relays
Intelligent Message Routing: Automatically chooses the best transport, with queuing and retry when a peer is unreachable
End-to-End Encryption: Noise Protocol (XX pattern, X25519 + ChaCha20-Poly1305) for private messages over the mesh
Decentralized Mesh Network: Automatic peer discovery and multi-hop relay over Bluetooth LE (max 7 hops)
Wi-Fi Aware Transport: Higher-bandwidth local mesh on supported devices
Channel Chats: Topic-based group messaging with optional password protection (Argon2id + AES-256-GCM)
IRC-Style Commands: Familiar /join, /msg, /who style interface
Tor Support: Built-in Tor (Arti) for private internet connectivity
Emergency Wipe: Triple-tap to instantly clear all data
Cross-Platform: Binary protocol compatible with bitchat on iOS and macOS

Technical Architecture

Bluetooth Mesh Network (Offline)

Direct peer-to-peer within Bluetooth range, multi-hop relay through nearby devices
Noise Protocol sessions with forward secrecy; peer identities derived from static keys
Compact binary packet format with fragmentation, TTL routing, and deduplication
Adaptive duty cycling and connection limits for battery efficiency
Foreground service keeps the mesh alive within Android background execution limits

Nostr Protocol (Internet)

Global reach via public relays, geohash-based location channels
Private messages fall back to Nostr for mutual favorites when the mesh is unavailable
Ephemeral keys per geohash area

Android Stack

Kotlin, Jetpack Compose (Material 3), MVVM
Coroutines and Flow for all networking and state
Core components: MeshForegroundService (persistent connectivity), BluetoothMeshService / WifiAwareMeshService (transports), UnifiedMeshService (transport selection), NoiseSessionManager (encryption sessions), MessageRouter (mesh/Nostr routing with outbox retry)

Building

Requires Android Studio and the Android SDK (API 26+).

github.com/permissionlesstech/bitchat-android.git cd bitchat-android ./gradlew assembleDebug">

git clone github.com/permissionlesstech/bitchat-android.git cd bitchat-android ./gradlew assembleDebug

Install on a connected device:

adb install -r app/build/outputs/apk/debug/app-debug.apk

The app requests Bluetooth, location (required for BLE scanning), and notification permissions at runtime.

Release APKs and the Android App Bundle can be rebuilt byte-for-byte in the pinned Linux container. Maintainers should follow the Android release guide. See Reproducible builds for the build trust model and public GitHub/Google Play verification procedures.

Testing

# Unit tests ./gradlew test  # Lint ./gradlew lint  # Instrumented tests (requires a device or emulator) ./gradlew connectedAndroidTest

Note that BLE mesh behavior is difficult to emulate; protocol and session logic is covered by unit tests, while radio-level behavior needs real devices.

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