Set minSdkVersion to 23 (Android 6)

Signed-off-by: Tim Krüger <t@timkrueger.me>

app/build.gradle

@@ -42,7 +42,7 @@ android {
     namespace 'com.nextcloud.talk'
 
     defaultConfig {
-        minSdkVersion 21
+        minSdkVersion 23
         targetSdkVersion 31
         testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
 

app/src/main/java/com/nextcloud/talk/activities/BaseActivity.kt

@@ -22,7 +22,6 @@ package com.nextcloud.talk.activities
 
 import android.annotation.SuppressLint
 import android.content.Context
-import android.os.Build
 import android.os.Bundle
 import android.util.Log
 import android.view.WindowManager
@@ -76,9 +75,7 @@ open class BaseActivity : AppCompatActivity() {
         }
 
         if (appPreferences.isScreenLocked) {
-            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
-                SecurityUtils.createKey(appPreferences.screenLockTimeout)
-            }
+            SecurityUtils.createKey(appPreferences.screenLockTimeout)
         }
     }
 

app/src/main/java/com/nextcloud/talk/activities/CallActivity.java

@@ -732,10 +732,8 @@ public class CallActivity extends CallBaseActivity {
         } else {
             if (EffortlessPermissions.hasPermissions(this, PERMISSIONS_CALL)) {
                 onPermissionsGranted();
-            } else if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
-                requestPermissions(PERMISSIONS_CALL, 100);
             } else {
-                onRequestPermissionsResult(100, PERMISSIONS_CALL, new int[]{1, 1});
+                requestPermissions(PERMISSIONS_CALL, 100);
             }
         }
 
@@ -980,11 +978,7 @@ public class CallActivity extends CallBaseActivity {
                 R.string.nc_microphone_permission_permanently_denied,
                 R.string.nc_permissions_settings, (AppCompatActivity) this);
         } else {
-            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
-                requestPermissions(PERMISSIONS_MICROPHONE, 100);
-            } else {
-                onRequestPermissionsResult(100, PERMISSIONS_MICROPHONE, new int[]{1});
-            }
+            requestPermissions(PERMISSIONS_MICROPHONE, 100);
         }
     }
 
@@ -1017,12 +1011,7 @@ public class CallActivity extends CallBaseActivity {
                 R.string.nc_camera_permission_permanently_denied,
                 R.string.nc_permissions_settings, (AppCompatActivity) this);
         } else {
-
-            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
-                requestPermissions(PERMISSIONS_CAMERA, 100);
-            } else {
-                onRequestPermissionsResult(100, PERMISSIONS_CAMERA, new int[]{1});
-            }
+            requestPermissions(PERMISSIONS_CAMERA, 100);
         }
 
     }

app/src/main/java/com/nextcloud/talk/activities/MainActivity.kt

@@ -24,12 +24,10 @@ package com.nextcloud.talk.activities
 import android.app.KeyguardManager
 import android.content.Context
 import android.content.Intent
-import android.os.Build
 import android.os.Bundle
 import android.provider.ContactsContract
 import android.text.TextUtils
 import android.util.Log
-import androidx.annotation.RequiresApi
 import autodagger.AutoInjector
 import com.bluelinelabs.conductor.Conductor
 import com.bluelinelabs.conductor.Router
@@ -148,10 +146,7 @@ class MainActivity : BaseActivity(), ActionBarProvider {
         super.onStart()
         Log.d(TAG, "onStart: Activity: " + System.identityHashCode(this).toString())
         logRouterBackStack(router!!)
-
-        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
-            lockScreenIfConditionsApply()
-        }
+        lockScreenIfConditionsApply()
     }
 
     override fun onResume() {
@@ -323,7 +318,6 @@ class MainActivity : BaseActivity(), ActionBarProvider {
             })
     }
 
-    @RequiresApi(api = Build.VERSION_CODES.M)
     fun lockScreenIfConditionsApply() {
         val keyguardManager = getSystemService(Context.KEYGUARD_SERVICE) as KeyguardManager
         if (keyguardManager.isKeyguardSecure && appPreferences.isScreenLocked) {

app/src/main/java/com/nextcloud/talk/application/NextcloudTalkApplication.kt

@@ -64,7 +64,6 @@ import com.nextcloud.talk.jobs.SignalingSettingsWorker
 import com.nextcloud.talk.ui.theme.ThemeModule
 import com.nextcloud.talk.utils.ClosedInterfaceImpl
 import com.nextcloud.talk.utils.DeviceUtils
-import com.nextcloud.talk.utils.DisplayUtils
 import com.nextcloud.talk.utils.NotificationUtils
 import com.nextcloud.talk.utils.database.arbitrarystorage.ArbitraryStorageModule
 import com.nextcloud.talk.utils.database.user.UserModule
@@ -163,7 +162,6 @@ class NextcloudTalkApplication : MultiDexApplication(), LifecycleObserver {
         securityKeyManager.init(this, securityKeyConfig)
 
         initializeWebRtc()
-        DisplayUtils.useCompatVectorIfNeeded()
         buildComponent()
         DavUtils.registerCustomFactories()
 

app/src/main/java/com/nextcloud/talk/controllers/ChatController.kt

@@ -1149,14 +1149,10 @@ class ChatController(args: Bundle) :
     }
 
     private fun isRecordAudioPermissionGranted(): Boolean {
-        return if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
-            return PermissionChecker.checkSelfPermission(
-                context,
-                Manifest.permission.RECORD_AUDIO
-            ) == PermissionChecker.PERMISSION_GRANTED
-        } else {
-            true
-        }
+        return PermissionChecker.checkSelfPermission(
+            context,
+            Manifest.permission.RECORD_AUDIO
+        ) == PermissionChecker.PERMISSION_GRANTED
     }
 
     private fun startAudioRecording(file: String) {

app/src/main/java/com/nextcloud/talk/controllers/LocationPickerController.kt

@@ -442,23 +442,19 @@ class LocationPickerController(args: Bundle) :
     private fun isLocationPermissionsGranted(): Boolean {
         fun isCoarseLocationGranted(): Boolean {
             return PermissionChecker.checkSelfPermission(
-                context!!,
+                context,
                 Manifest.permission.ACCESS_COARSE_LOCATION
             ) == PermissionChecker.PERMISSION_GRANTED
         }
 
         fun isFineLocationGranted(): Boolean {
             return PermissionChecker.checkSelfPermission(
-                context!!,
+                context,
                 Manifest.permission.ACCESS_FINE_LOCATION
             ) == PermissionChecker.PERMISSION_GRANTED
         }
 
-        return if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
-            isCoarseLocationGranted() && isFineLocationGranted()
-        } else {
-            true
-        }
+        return isCoarseLocationGranted() && isFineLocationGranted()
     }
 
     private fun requestLocationPermissions() {

app/src/main/java/com/nextcloud/talk/controllers/LockedController.kt

@@ -25,12 +25,10 @@ import android.app.Activity
 import android.app.KeyguardManager
 import android.content.Context
 import android.content.Intent
-import android.os.Build
 import android.os.Handler
 import android.os.Looper
 import android.util.Log
 import android.view.View
-import androidx.annotation.RequiresApi
 import androidx.biometric.BiometricPrompt
 import androidx.biometric.BiometricPrompt.PromptInfo
 import androidx.core.content.res.ResourcesCompat
@@ -62,15 +60,11 @@ class LockedController : BaseController(R.layout.controller_locked) {
     override fun onViewBound(view: View) {
         super.onViewBound(view)
         sharedApplication!!.componentApplication.inject(this)
-
-        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
-            binding.unlockContainer.setOnClickListener {
-                unlock()
-            }
+        binding.unlockContainer.setOnClickListener {
+            unlock()
         }
     }
 
-    @RequiresApi(api = Build.VERSION_CODES.M)
     override fun onAttach(view: View) {
         super.onAttach(view)
         Log.d(TAG, "onAttach")
@@ -92,12 +86,10 @@ class LockedController : BaseController(R.layout.controller_locked) {
         Log.d(TAG, "onDetach")
     }
 
-    @RequiresApi(api = Build.VERSION_CODES.M)
     fun unlock() {
         checkIfWeAreSecure()
     }
 
-    @RequiresApi(api = Build.VERSION_CODES.M)
     private fun showBiometricDialog() {
         val context: Context? = activity
         if (context != null) {
@@ -140,11 +132,10 @@ class LockedController : BaseController(R.layout.controller_locked) {
         }
     }
 
-    @RequiresApi(api = Build.VERSION_CODES.M)
     private fun checkIfWeAreSecure() {
         val keyguardManager = activity?.getSystemService(Context.KEYGUARD_SERVICE) as KeyguardManager?
-        if (keyguardManager?.isKeyguardSecure == true && appPreferences!!.isScreenLocked) {
-            if (!SecurityUtils.checkIfWeAreAuthenticated(appPreferences!!.screenLockTimeout)) {
+        if (keyguardManager?.isKeyguardSecure == true && appPreferences.isScreenLocked) {
+            if (!SecurityUtils.checkIfWeAreAuthenticated(appPreferences.screenLockTimeout)) {
                 Log.d(TAG, "showBiometricDialog because 'we are NOT authenticated'...")
                 showBiometricDialog()
             } else {
@@ -172,8 +163,7 @@ class LockedController : BaseController(R.layout.controller_locked) {
         if (requestCode == REQUEST_CODE_CONFIRM_DEVICE_CREDENTIALS) {
             if (resultCode == Activity.RESULT_OK) {
                 if (
-                    Build.VERSION.SDK_INT >= Build.VERSION_CODES.M &&
-                    SecurityUtils.checkIfWeAreAuthenticated(appPreferences!!.screenLockTimeout)
+                    SecurityUtils.checkIfWeAreAuthenticated(appPreferences.screenLockTimeout)
                 ) {
                     Log.d(TAG, "All went well, dismiss locked controller")
                     router.popCurrentController()

app/src/main/java/com/nextcloud/talk/controllers/SettingsController.kt

@@ -157,18 +157,13 @@ class SettingsController : BaseController(R.layout.controller_settings) {
             binding.settingsIncognitoKeyboard.visibility = View.GONE
         }
 
-        if (Build.VERSION.SDK_INT < Build.VERSION_CODES.M) {
-            binding.settingsScreenLock.visibility = View.GONE
-            binding.settingsScreenLockTimeout.visibility = View.GONE
-        } else {
-            binding.settingsScreenLock.setSummary(
-                String.format(
-                    Locale.getDefault(),
-                    resources!!.getString(R.string.nc_settings_screen_lock_desc),
-                    resources!!.getString(R.string.nc_app_product_name)
-                )
+        binding.settingsScreenLock.setSummary(
+            String.format(
+                Locale.getDefault(),
+                resources!!.getString(R.string.nc_settings_screen_lock_desc),
+                resources!!.getString(R.string.nc_app_product_name)
             )
-        }
+        )
 
         setupPrivacyUrl()
         setupSourceCodeUrl()
@@ -662,10 +657,8 @@ class SettingsController : BaseController(R.layout.controller_settings) {
                 appPreferences.isKeyboardIncognito
         }
 
-        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
-            (binding.settingsIncognitoKeyboard.findViewById<View>(R.id.mp_checkable) as Checkable).isChecked =
-                appPreferences.isKeyboardIncognito
-        }
+        (binding.settingsIncognitoKeyboard.findViewById<View>(R.id.mp_checkable) as Checkable).isChecked =
+            appPreferences.isKeyboardIncognito
 
         if (CapabilitiesUtilNew.isReadStatusAvailable(userManager.currentUser.blockingGet())) {
             (binding.settingsReadPrivacy.findViewById<View>(R.id.mp_checkable) as Checkable).isChecked =
@@ -679,29 +672,27 @@ class SettingsController : BaseController(R.layout.controller_settings) {
     }
 
     private fun setupScreenLockSetting() {
-        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
-            val keyguardManager = context.getSystemService(Context.KEYGUARD_SERVICE) as KeyguardManager
-            if (keyguardManager.isKeyguardSecure) {
-                binding.settingsScreenLock.isEnabled = true
-                binding.settingsScreenLockTimeout.isEnabled = true
-                (binding.settingsScreenLock.findViewById<View>(R.id.mp_checkable) as Checkable).isChecked =
-                    appPreferences.isScreenLocked
-                binding.settingsScreenLockTimeout.isEnabled = appPreferences.isScreenLocked
-                if (appPreferences.isScreenLocked) {
-                    binding.settingsScreenLockTimeout.alpha = ENABLED_ALPHA
-                } else {
-                    binding.settingsScreenLockTimeout.alpha = DISABLED_ALPHA
-                }
-                binding.settingsScreenLock.alpha = ENABLED_ALPHA
+        val keyguardManager = context.getSystemService(Context.KEYGUARD_SERVICE) as KeyguardManager
+        if (keyguardManager.isKeyguardSecure) {
+            binding.settingsScreenLock.isEnabled = true
+            binding.settingsScreenLockTimeout.isEnabled = true
+            (binding.settingsScreenLock.findViewById<View>(R.id.mp_checkable) as Checkable).isChecked =
+                appPreferences.isScreenLocked
+            binding.settingsScreenLockTimeout.isEnabled = appPreferences.isScreenLocked
+            if (appPreferences.isScreenLocked) {
+                binding.settingsScreenLockTimeout.alpha = ENABLED_ALPHA
             } else {
-                binding.settingsScreenLock.isEnabled = false
-                binding.settingsScreenLockTimeout.isEnabled = false
-                appPreferences.removeScreenLock()
-                appPreferences.removeScreenLockTimeout()
-                (binding.settingsScreenLock.findViewById<View>(R.id.mp_checkable) as Checkable).isChecked = false
-                binding.settingsScreenLock.alpha = DISABLED_ALPHA
                 binding.settingsScreenLockTimeout.alpha = DISABLED_ALPHA
             }
+            binding.settingsScreenLock.alpha = ENABLED_ALPHA
+        } else {
+            binding.settingsScreenLock.isEnabled = false
+            binding.settingsScreenLockTimeout.isEnabled = false
+            appPreferences.removeScreenLock()
+            appPreferences.removeScreenLockTimeout()
+            (binding.settingsScreenLock.findViewById<View>(R.id.mp_checkable) as Checkable).isChecked = false
+            binding.settingsScreenLock.alpha = DISABLED_ALPHA
+            binding.settingsScreenLockTimeout.alpha = DISABLED_ALPHA
         }
     }
 
@@ -805,9 +796,7 @@ class SettingsController : BaseController(R.layout.controller_settings) {
 
     private inner class ScreenLockTimeoutListener : OnPreferenceValueChangedListener<String?> {
         override fun onChanged(newValue: String?) {
-            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
-                SecurityUtils.createKey(appPreferences.screenLockTimeout)
-            }
+            SecurityUtils.createKey(appPreferences.screenLockTimeout)
         }
     }
 

app/src/main/java/com/nextcloud/talk/jobs/NotificationWorker.kt

@@ -447,11 +447,9 @@ class NotificationWorker(context: Context, workerParams: WorkerParameters) : Wor
                 EmojiCompat.get().process(pushMessage.text!!)
             )
         }
-        if (Build.VERSION.SDK_INT >= 23) {
-            // This method should exist since API 21, but some phones don't have it
-            // So as a safeguard, we don't use it until 23
-            notificationBuilder.color = context!!.resources.getColor(R.color.colorPrimary)
-        }
+
+        notificationBuilder.color = context!!.resources.getColor(R.color.colorPrimary)
+
         val notificationInfoBundle = Bundle()
         notificationInfoBundle.putLong(KEY_INTERNAL_USER_ID, signatureVerification.user!!.id!!)
         // could be an ID or a TOKEN
@@ -694,7 +692,6 @@ class NotificationWorker(context: Context, workerParams: WorkerParameters) : Wor
             .subscribe(object : Observer<ParticipantsOverall> {
                 override fun onSubscribe(d: Disposable) = Unit
 
-                @RequiresApi(Build.VERSION_CODES.M)
                 override fun onNext(participantsOverall: ParticipantsOverall) {
                     val participantList: List<Participant> = participantsOverall.ocs!!.data!!
                     hasParticipantsInCall = participantList.isNotEmpty()
@@ -726,7 +723,6 @@ class NotificationWorker(context: Context, workerParams: WorkerParameters) : Wor
                     Log.e(TAG, "Error in getPeersForCall", e)
                 }
 
-                @RequiresApi(Build.VERSION_CODES.M)
                 override fun onComplete() {
 
                     if (isCallNotificationVisible) {
@@ -821,7 +817,6 @@ class NotificationWorker(context: Context, workerParams: WorkerParameters) : Wor
         return PendingIntent.getActivity(context, requestCode, intent, intentFlag)
     }
 
-    @RequiresApi(Build.VERSION_CODES.M)
     private fun isCallNotificationVisible(decryptedPushMessage: DecryptedPushMessage): Boolean {
         var isVisible = false
 

app/src/main/java/com/nextcloud/talk/jobs/UploadAndShareFilesWorker.kt

@@ -295,7 +295,7 @@ class UploadAndShareFilesWorker(val context: Context, workerParameters: WorkerPa
                         false
                     }
                 }
-                Build.VERSION.SDK_INT >= Build.VERSION_CODES.M -> {
+                else -> {
                     if (PermissionChecker.checkSelfPermission(
                             context,
                             Manifest.permission.WRITE_EXTERNAL_STORAGE
@@ -308,10 +308,6 @@ class UploadAndShareFilesWorker(val context: Context, workerParameters: WorkerPa
                         false
                     }
                 }
-                else -> { // permission is automatically granted on sdk<23 upon installation
-                    Log.d(TAG, "Permission is granted")
-                    true
-                }
             }
         }
 
@@ -325,7 +321,7 @@ class UploadAndShareFilesWorker(val context: Context, workerParameters: WorkerPa
                         REQUEST_PERMISSION
                     )
                 }
-                Build.VERSION.SDK_INT >= Build.VERSION_CODES.M -> {
+                else -> {
                     controller.requestPermissions(
                         arrayOf(
                             Manifest.permission.WRITE_EXTERNAL_STORAGE
@@ -333,8 +329,6 @@ class UploadAndShareFilesWorker(val context: Context, workerParameters: WorkerPa
                         REQUEST_PERMISSION
                     )
                 }
-                else -> { // permission is automatically granted on sdk<23 upon installation
-                }
             }
         }
 

app/src/main/java/com/nextcloud/talk/utils/DisplayUtils.java

@@ -24,7 +24,6 @@
 
 package com.nextcloud.talk.utils;
 
-import android.annotation.SuppressLint;
 import android.app.Activity;
 import android.content.Context;
 import android.content.Intent;
@@ -67,9 +66,6 @@ import com.nextcloud.talk.utils.text.Spans;
 
 import org.greenrobot.eventbus.EventBus;
 
-import java.lang.reflect.Constructor;
-import java.lang.reflect.InvocationTargetException;
-import java.lang.reflect.Method;
 import java.text.DateFormat;
 import java.util.Date;
 import java.util.regex.Matcher;
@@ -82,7 +78,6 @@ import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
 import androidx.annotation.StringRes;
 import androidx.annotation.XmlRes;
-import androidx.appcompat.widget.AppCompatDrawableManager;
 import androidx.core.content.ContextCompat;
 import androidx.core.content.res.ResourcesCompat;
 import androidx.core.graphics.ColorUtils;
@@ -155,31 +150,6 @@ public class DisplayUtils {
         return px / context.getResources().getDisplayMetrics().density;
     }
 
-    // Solution inspired by https://stackoverflow.com/questions/34936590/why-isnt-my-vector-drawable-scaling-as-expected
-    public static void useCompatVectorIfNeeded() {
-        if (Build.VERSION.SDK_INT < 23) {
-            try {
-                @SuppressLint("RestrictedApi") AppCompatDrawableManager drawableManager = AppCompatDrawableManager.get();
-                Class<?> inflateDelegateClass = Class.forName(
-                    "android.support.v7.widget.AppCompatDrawableManager$InflateDelegate");
-                Class<?> vdcInflateDelegateClass = Class.forName(
-                    "android.support.v7.widget.AppCompatDrawableManager$VdcInflateDelegate");
-
-                Constructor<?> constructor = vdcInflateDelegateClass.getDeclaredConstructor();
-                constructor.setAccessible(true);
-                Object vdcInflateDelegate = constructor.newInstance();
-
-                Class<?> args[] = {String.class, inflateDelegateClass};
-                Method addDelegate = AppCompatDrawableManager.class.getDeclaredMethod("addDelegate", args);
-                addDelegate.setAccessible(true);
-                addDelegate.invoke(drawableManager, "vector", vdcInflateDelegate);
-            } catch (ClassNotFoundException | NoSuchMethodException | InstantiationException |
-                InvocationTargetException | IllegalAccessException e) {
-                Log.e(TAG, "Failed to use reflection to enable proper vector scaling");
-            }
-        }
-    }
-
     public static Drawable getTintedDrawable(Resources res, @DrawableRes int drawableResId, @ColorRes int colorResId) {
         Drawable drawable = ResourcesCompat.getDrawable(res, drawableResId, null);
 
@@ -206,10 +176,8 @@ public class DisplayUtils {
             viewThemeUtils.material.colorChipDrawable(context, chip);
         }
 
-        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
-            Configuration config = context.getResources().getConfiguration();
-            chip.setLayoutDirection(config.getLayoutDirection());
-        }
+        Configuration config = context.getResources().getConfiguration();
+        chip.setLayoutDirection(config.getLayoutDirection());
 
         int drawable;
 
@@ -386,24 +354,23 @@ public class DisplayUtils {
         Window window = activity.getWindow();
         boolean isLightTheme = lightTheme(color);
         if (window != null) {
-            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
-                View decor = window.getDecorView();
-                if (isLightTheme) {
-                    int systemUiFlagLightStatusBar;
-                    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
-                        systemUiFlagLightStatusBar = View.SYSTEM_UI_FLAG_LIGHT_STATUS_BAR |
-                            View.SYSTEM_UI_FLAG_LIGHT_NAVIGATION_BAR;
-                    } else {
-                        systemUiFlagLightStatusBar = View.SYSTEM_UI_FLAG_LIGHT_STATUS_BAR;
-                    }
-                    decor.setSystemUiVisibility(systemUiFlagLightStatusBar);
+
+            View decor = window.getDecorView();
+            if (isLightTheme) {
+                int systemUiFlagLightStatusBar;
+                if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
+                    systemUiFlagLightStatusBar = View.SYSTEM_UI_FLAG_LIGHT_STATUS_BAR |
+                        View.SYSTEM_UI_FLAG_LIGHT_NAVIGATION_BAR;
                 } else {
-                    decor.setSystemUiVisibility(0);
+                    systemUiFlagLightStatusBar = View.SYSTEM_UI_FLAG_LIGHT_STATUS_BAR;
                 }
-                window.setStatusBarColor(color);
-            } else if (isLightTheme) {
-                window.setStatusBarColor(Color.BLACK);
+                decor.setSystemUiVisibility(systemUiFlagLightStatusBar);
+            } else {
+                decor.setSystemUiVisibility(0);
             }
+            window.setStatusBarColor(color);
+        } else if (isLightTheme) {
+            window.setStatusBarColor(Color.BLACK);
         }
     }
 

app/src/main/java/com/nextcloud/talk/utils/NotificationUtils.kt

@@ -218,7 +218,7 @@ object NotificationUtils {
             notification: Notification
         ) -> Unit
     ) {
-        if (Build.VERSION.SDK_INT < Build.VERSION_CODES.M || conversationUser.id == -1L || context == null) {
+        if (conversationUser.id == -1L || context == null) {
             return
         }
 

app/src/main/java/com/nextcloud/talk/utils/SecurityUtils.java

@@ -21,7 +21,6 @@
 package com.nextcloud.talk.utils;
 
 import android.content.res.Resources;
-import android.os.Build;
 import android.security.keystore.KeyGenParameterSpec;
 import android.security.keystore.KeyPermanentlyInvalidatedException;
 import android.security.keystore.KeyProperties;
@@ -50,7 +49,6 @@ import javax.crypto.KeyGenerator;
 import javax.crypto.NoSuchPaddingException;
 import javax.crypto.SecretKey;
 
-import androidx.annotation.RequiresApi;
 import androidx.biometric.BiometricPrompt;
 
 public class SecurityUtils {
@@ -60,7 +58,6 @@ public class SecurityUtils {
 
     private static BiometricPrompt.CryptoObject cryptoObject;
 
-    @RequiresApi(api = Build.VERSION_CODES.M)
     public static boolean checkIfWeAreAuthenticated(String screenLockTimeout) {
         try {
             KeyStore keyStore = KeyStore.getInstance("AndroidKeyStore");
@@ -95,12 +92,10 @@ public class SecurityUtils {
         }
     }
 
-    @RequiresApi(api = Build.VERSION_CODES.M)
     public static BiometricPrompt.CryptoObject getCryptoObject() {
         return cryptoObject;
     }
 
-    @RequiresApi(api = Build.VERSION_CODES.M)
     public static void createKey(String validity) {
         try {
             KeyStore keyStore = KeyStore.getInstance("AndroidKeyStore");

app/src/main/java/com/nextcloud/talk/utils/permissions/PlatformPermissionUtilImpl.kt

@@ -23,7 +23,6 @@ package com.nextcloud.talk.utils.permissions
 
 import android.Manifest
 import android.content.Context
-import android.os.Build
 import androidx.core.content.PermissionChecker
 import com.nextcloud.talk.BuildConfig
 
@@ -32,13 +31,9 @@ class PlatformPermissionUtilImpl(private val context: Context) : PlatformPermiss
         "${BuildConfig.APPLICATION_ID}.${BuildConfig.PERMISSION_LOCAL_BROADCAST}"
 
     override fun isCameraPermissionGranted(): Boolean {
-        return if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
-            return PermissionChecker.checkSelfPermission(
-                context,
-                Manifest.permission.CAMERA
-            ) == PermissionChecker.PERMISSION_GRANTED
-        } else {
-            true
-        }
+        return PermissionChecker.checkSelfPermission(
+            context,
+            Manifest.permission.CAMERA
+        ) == PermissionChecker.PERMISSION_GRANTED
     }
 }

app/src/main/java/com/nextcloud/talk/utils/ssl/SSLSocketFactoryCompat.kt

@@ -8,12 +8,9 @@
 
 package com.nextcloud.talk.utils.ssl
 
-import android.os.Build
-import java.io.IOException
 import java.net.InetAddress
 import java.net.Socket
 import java.security.GeneralSecurityException
-import java.util.LinkedList
 import javax.net.ssl.KeyManager
 import javax.net.ssl.SSLContext
 import javax.net.ssl.SSLSocket
@@ -35,69 +32,12 @@ class SSLSocketFactoryCompat(
         var cipherSuites: Array<String>? = null
 
         init {
-            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
-                // Since Android 6.0 (API level 23),
-                // - TLSv1.1 and TLSv1.2 is enabled by default
-                // - SSLv3 is disabled by default
-                // - all modern ciphers are activated by default
-                protocols = null
-                cipherSuites = null
-            } else {
-                val socket = SSLSocketFactory.getDefault().createSocket() as SSLSocket?
-                try {
-                    socket?.let {
-                        /* set reasonable protocol versions */
-                        // - enable all supported protocols (enables TLSv1.1 and TLSv1.2 on Android <5.0)
-                        // - remove all SSL versions (especially SSLv3) because they're insecure now
-                        val _protocols = LinkedList<String>()
-                        for (protocol in socket.supportedProtocols.filterNot { it.contains("SSL", true) })
-                            _protocols += protocol
-                        protocols = _protocols.toTypedArray()
-
-                        /* set up reasonable cipher suites */
-                        val knownCiphers = arrayOf<String>(
-                            // TLS 1.2
-                            "TLS_RSA_WITH_AES_256_GCM_SHA384",
-                            "TLS_RSA_WITH_AES_128_GCM_SHA256",
-                            "TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256",
-                            "TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256",
-                            "TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384",
-                            "TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256",
-                            "TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256",
-                            // maximum interoperability
-                            "TLS_RSA_WITH_3DES_EDE_CBC_SHA",
-                            "SSL_RSA_WITH_3DES_EDE_CBC_SHA",
-                            "TLS_RSA_WITH_AES_128_CBC_SHA",
-                            // additionally
-                            "TLS_RSA_WITH_AES_256_CBC_SHA",
-                            "TLS_ECDHE_ECDSA_WITH_3DES_EDE_CBC_SHA",
-                            "TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA",
-                            "TLS_ECDHE_RSA_WITH_3DES_EDE_CBC_SHA",
-                            "TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA"
-                        )
-                        val availableCiphers = socket.supportedCipherSuites
-
-                        /* For maximum security, preferredCiphers should *replace* enabled ciphers (thus
-                         * disabling ciphers which are enabled by default, but have become unsecure), but for
-                         * the security level of DAVdroid and maximum compatibility, disabling of insecure
-                         * ciphers should be a server-side task */
-
-                        // for the final set of enabled ciphers, take the ciphers enabled by default, ...
-                        val _cipherSuites = LinkedList<String>()
-                        _cipherSuites.addAll(socket.enabledCipherSuites)
-                        // ... add explicitly allowed ciphers ...
-                        _cipherSuites.addAll(knownCiphers)
-                        // ... and keep only those which are actually available
-                        _cipherSuites.retainAll(availableCiphers)
-
-                        cipherSuites = _cipherSuites.toTypedArray()
-                    }
-                } catch (e: IOException) {
-                    // Exception is to be ignored
-                } finally {
-                    socket?.close() // doesn't implement Closeable on all supported Android versions
-                }
-            }
+            // Since Android 6.0 (API level 23),
+            // - TLSv1.1 and TLSv1.2 is enabled by default
+            // - SSLv3 is disabled by default
+            // - all modern ciphers are activated by default
+            protocols = null
+            cipherSuites = null
         }
     }
 

app/src/main/java/com/nextcloud/talk/webrtc/WebRtcAudioManager.java

@@ -41,7 +41,6 @@ import android.content.IntentFilter;
 import android.content.pm.PackageManager;
 import android.media.AudioDeviceInfo;
 import android.media.AudioManager;
-import android.os.Build;
 import android.util.Log;
 
 import com.nextcloud.talk.events.PeerConnectionEvent;
@@ -388,22 +387,18 @@ public class WebRtcAudioManager {
      */
     @Deprecated
     private boolean hasWiredHeadset() {
-        if (Build.VERSION.SDK_INT < Build.VERSION_CODES.M) {
-            return audioManager.isWiredHeadsetOn();
-        } else {
-            @SuppressLint("WrongConstant") final AudioDeviceInfo[] devices = audioManager.getDevices(AudioManager.GET_DEVICES_ALL);
-            for (AudioDeviceInfo device : devices) {
-                final int type = device.getType();
-                if (type == AudioDeviceInfo.TYPE_WIRED_HEADSET) {
-                    Log.d(TAG, "hasWiredHeadset: found wired headset");
-                    return true;
-                } else if (type == AudioDeviceInfo.TYPE_USB_DEVICE) {
-                    Log.d(TAG, "hasWiredHeadset: found USB audio device");
-                    return true;
-                }
+        @SuppressLint("WrongConstant") final AudioDeviceInfo[] devices = audioManager.getDevices(AudioManager.GET_DEVICES_ALL);
+        for (AudioDeviceInfo device : devices) {
+            final int type = device.getType();
+            if (type == AudioDeviceInfo.TYPE_WIRED_HEADSET) {
+                Log.d(TAG, "hasWiredHeadset: found wired headset");
+                return true;
+            } else if (type == AudioDeviceInfo.TYPE_USB_DEVICE) {
+                Log.d(TAG, "hasWiredHeadset: found USB audio device");
+                return true;
             }
-            return false;
         }
+        return false;
     }
 
     public void updateAudioDeviceState() {