Converted to target SDK Level 28 - had to change how we did notifications, and specify a style to get back to black background. Still a problem with the 'ok' notification not displaying properly - background showing white for some reason.

app/build.gradle

@@ -1,13 +1,14 @@
 apply plugin: 'com.android.application'
 
 android {
-    compileSdkVersion 24
+    compileSdkVersion 28
     useLibrary  'org.apache.http.legacy'
 
     defaultConfig {
         applicationId "uk.org.openseizuredetector"
-        minSdkVersion 14
-        targetSdkVersion 14
+        minSdkVersion 19
+        targetSdkVersion 28
+        multiDexEnabled true
     }
 
     buildTypes {
@@ -32,8 +33,8 @@ dependencies {
     testImplementation 'org.mockito:mockito-core:1.10.19'
     // Set this dependency if you want to use Hamcrest matching
     testImplementation 'org.hamcrest:hamcrest-library:1.1'
-    implementation 'com.android.support:appcompat-v7:22.2.1'
-    implementation 'com.android.support:support-v4:22.2.1'
+    implementation 'com.android.support:appcompat-v7:28.0.0'
+    implementation 'com.android.support:support-v4:28.0.0'
     //compile files('libs/JTransforms-3.1-with-dependencies.jar')
     implementation 'org.apache.commons:commons-math3:3.6.1'
     // google play services used for location finding for SMS alerts.