updated project

android/app/build.gradle

@@ -25,7 +25,7 @@ if (flutterVersionName == null) {
 android {
     namespace "eu.mhsl.marianum.mobile.client"
     compileSdk flutter.compileSdkVersion
-    ndkVersion flutter.ndkVersion
+    ndkVersion "27.0.12077973"
 
     compileOptions {
         sourceCompatibility JavaVersion.VERSION_1_8
@@ -41,11 +41,8 @@ android {
     }
 
     defaultConfig {
-        // TODO: Specify your own unique Application ID (https://developer.android.com/studio/build/application-id.html).
         applicationId "eu.mhsl.marianum.mobile.client"
-        // You can update the following values to match your application needs.
-        // For more information, see: https://docs.flutter.dev/deployment/android#reviewing-the-gradle-build-configuration.
-        minSdkVersion 21
+        minSdkVersion 26
         targetSdkVersion flutter.targetSdkVersion
         versionCode flutterVersionCode.toInteger()
         versionName flutterVersionName
@@ -66,5 +63,6 @@ flutter {
 }
 
 dependencies {
-    implementation 'com.android.support:multidex:1.0.3'
+    implementation 'com.android.support:multidex:2.0.1'
+    implementation 'com.android.tools:desugar_jdk_libs:2.0.3'
 }