Add building instructions for Debian 13 and bump Java version

Author: Golbinex

BUILDING.md

@@ -0,0 +1,39 @@
+## Building instructions for Debian 13
+
+1. Install necessary software
+      - `sudo apt install cmake golang gperf meson ninja-build sdkmanager wget yasm`
+      - `sudo apt install google-android-platform-35-installer google-android-build-tools-35.0.0-installer google-android-ndk-r21e-installer google-android-ndk-r23c-installer openjdk-21-jdk-headless`
+
+2. Don't forget to include the submodules when you clone:
+      - `git clone --recursive https://github.com/forkgram/TelegramAndroid.git`
+
+3. Build native FFmpeg and BoringSSL dependencies:
+      - Go to the `TMessagesProj/jni` folder and execute the following (define the paths to your NDK and Ninja):
+
+      ```
+      export NDK=/usr/lib/android-sdk/ndk/21.4.7075529
+      export NINJA_PATH=/usr/bin/ninja
+      export ANDROID_SDK=/usr/lib/android-sdk
+      export ANDROID_HOME=/usr/lib/android-sdk
+      sudo sdkmanager "cmake;3.22.1" --sdk_root /usr/lib/android-sdk
+      ./build_libvpx_clang.sh
+      ./build_ffmpeg_clang.sh
+      ./patch_ffmpeg.sh
+      ./patch_boringssl.sh
+      ./build_boringssl.sh
+      ```
+
+4. If you want to publish a modified version of Telegram:
+      - You should get **your own API key** here: https://core.telegram.org/api/obtaining_api_id and edit a file called `gradle.properties` in the source root directory.
+        The contents should look like this:
+        ```
+        APP_ID = 12345
+        APP_HASH = aaaaaaaabbbbbbccccccfffffff001122
+        ```
+      - Do not use the name Telegram and the standard logo (white paper plane in a blue circle) for your app — or make sure your users understand that it is unofficial
+      - Take good care of your users' data and privacy
+      - **Please remember to publish your code too in order to comply with the licenses**
+
+The project can be built with Android Studio or from the command line with gradle:
+
+`./gradlew assembleAfatRelease`

README.md

@@ -52,3 +52,6 @@ Fork Client is a fork of the official Telegram for Android application.
 
 ## Downloads:
 You can download binaries from Releases or from my [Telegram channel Forkgram](https://t.me/forkgram).
+
+## Building instructions for Debian 13:
+[BUILDING.md](BUILDING.md)

TMessagesProj/build.gradle

@@ -92,8 +92,8 @@ android {
     }
 
     compileOptions {
-        sourceCompatibility JavaVersion.VERSION_17
-        targetCompatibility JavaVersion.VERSION_17
+        sourceCompatibility JavaVersion.VERSION_21
+        targetCompatibility JavaVersion.VERSION_21
 
         coreLibraryDesugaringEnabled true
     }