frontend/android: push min sdk version to 23 (Android 6)

Author: Beerosagos

backend/mobileserver/Makefile

@@ -4,7 +4,7 @@ include ../../version.mk.inc
 # Set -glflags to fix the vendor issue with gomobile, see: https://github.com/golang/go/issues/67927#issuecomment-2241523694
 build-android:
 	# androidapi version should match minSdkVersion in frontends/android/BitBoxApp/app/build.gradle
-	ANDROID_HOME=${ANDROID_SDK_ROOT} gomobile bind -x -a -glflags="-mod=readonly" -ldflags="-s -w $(GO_VERSION_LDFLAGS)" -trimpath -target android -androidapi 21 .
+	ANDROID_HOME=${ANDROID_SDK_ROOT} gomobile bind -x -a -glflags="-mod=readonly" -ldflags="-s -w $(GO_VERSION_LDFLAGS)" -trimpath -target android -androidapi 23 .
 build-ios:
 	gomobile bind -x -a -glflags="-mod=readonly" -tags="timetzdata" -trimpath -ldflags="-s -w $(GO_VERSION_LDFLAGS)" -target ios,iossimulator .
 clean:

frontends/android/BitBoxApp/app/build.gradle

@@ -15,7 +15,7 @@ android {
         applicationId "ch.shiftcrypto.bitboxapp"
         // minSdkVersion should match the `-androidapi` gomobile bind flag
         // in backend/mobileserver/Makefile
-        minSdkVersion 21
+        minSdkVersion 23
         targetSdkVersion 35
         versionCode 66
         versionName "${appVersion}"