Use vector icons.

app/src/main/AndroidManifest.xml

@@ -13,7 +13,7 @@
 
     <application
         android:allowBackup="true"
-        android:icon="@mipmap/ic_launcher"
+        android:icon="@drawable/ic_launcher"
         android:label="@string/app_name"
         android:theme="@style/AppTheme"
         android:name=".MainApplication">

app/src/main/java/org/traccar/client/ShortcutActivity.java

@@ -68,13 +68,13 @@ public class ShortcutActivity extends AppCompatActivity implements LostApiClient
                 public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
                     switch (position) {
                         case 0:
-                            setShortcutResult(items[position], R.mipmap.ic_start, ACTION_START);
+                            setShortcutResult(items[position], R.drawable.ic_start, ACTION_START);
                             break;
                         case 1:
-                            setShortcutResult(items[position], R.mipmap.ic_stop, ACTION_STOP);
+                            setShortcutResult(items[position], R.drawable.ic_stop, ACTION_STOP);
                             break;
                         case 2:
-                            setShortcutResult(items[position], R.mipmap.ic_sos, ACTION_SOS);
+                            setShortcutResult(items[position], R.drawable.ic_sos, ACTION_SOS);
                             break;
                     }
                     finish();

app/src/main/res/drawable/ic_launcher.xml

@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="utf-8"?>
 <adaptive-icon xmlns:android="http://schemas.android.com/apk/res/android">
     <background android:drawable="@color/primary"/>
-    <foreground android:drawable="@mipmap/ic_launcher_foreground"/>
+    <foreground android:drawable="@drawable/ic_launcher_foreground"/>
 </adaptive-icon>

app/src/main/res/drawable/ic_launcher_foreground.xml

@@ -0,0 +1,31 @@
+<vector
+    android:width="108dp"
+    android:height="108dp"
+    android:viewportHeight="108"
+    android:viewportWidth="108"
+    xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:aapt="http://schemas.android.com/aapt">
+    <group
+        android:translateX="18"
+        android:translateY="18">
+        <path
+            android:pathData="M36.37,10.65A25.35,25.35 0,0 0,18.08 18.08A25.35,25.35 0,0 0,18.08 53.92A25.35,25.35 0,0 0,18.99 54.77L56.29,92.08L92.14,56.23L53.96,18.04L53.92,18.08A25.35,25.35 0,0 0,36.37 10.65z"
+            android:strokeWidth="1.34557009">
+            <aapt:attr name="android:fillColor">
+                <gradient
+                    android:endX="74"
+                    android:endY="74"
+                    android:startX="36"
+                    android:startY="36"
+                    android:type="linear">
+                    <item android:color="#26000000" android:offset="0.32"/>
+                    <item android:color="#05000000" android:offset="0.62"/>
+                    <item android:color="#00000000" android:offset="1.0"/>
+                </gradient>
+            </aapt:attr>
+        </path>
+        <path
+            android:pathData="M36,10.61A25.39,25.39 0,0 0,10.61 36,25.39 25.39,0 0,0 36,61.39 25.39,25.39 0,0 0,61.39 36,25.39 25.39,0 0,0 36,10.61ZM46.23,20.95c2.05,1.57 3.83,3.54 5.2,5.92 1.37,2.38 2.19,4.9 2.53,7.46l-4.49,0.65c-0.26,-1.98 -0.86,-4.02 -1.93,-5.86 -1.06,-1.84 -2.53,-3.38 -4.11,-4.6zM40.81,28.13c1.12,0.87 2.09,1.93 2.84,3.23 0.75,1.3 1.19,2.67 1.38,4.07l-4.49,0.65C40.41,35.26 40.19,34.38 39.75,33.61 39.31,32.85 38.66,32.22 38,31.7ZM23.58,32.57 L28.07,40.35 32.57,48.14a8.99,8.99 37.68,0 1,-8.99 0,8.99 8.99,37.68 0,1 -4.49,-7.79 8.99,8.99 37.68,0 1,4.49 -7.79zM33.86,34.74a2.25,2.25 60,0 1,2 1.12,2.25 2.25,60 0,1 -0.82,3.07 2.25,2.25 60,0 1,-3.07 -0.82,2.25 2.25,60 0,1 0.82,-3.07 2.25,2.25 60,0 1,1.07 -0.3z"
+            android:fillColor="@color/white"/>
+    </group>
+</vector>

app/src/main/res/drawable/ic_sos.xml

@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="utf-8"?>
 <adaptive-icon xmlns:android="http://schemas.android.com/apk/res/android">
     <background android:drawable="@color/white"/>
-    <foreground android:drawable="@mipmap/ic_start_foreground"/>
+    <foreground android:drawable="@drawable/ic_sos_foreground"/>
 </adaptive-icon>

app/src/main/res/drawable/ic_sos_foreground.xml

@@ -0,0 +1,19 @@
+<!-- Based off of ic_error_black -->
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+        android:width="108dp"
+        android:height="108dp"
+        android:viewportWidth="36.0"
+        android:viewportHeight="36.0">
+    <group
+        android:translateX="6"
+        android:translateY="6"
+        android:scaleX="0.85"
+        android:scaleY="0.85"
+        android:pivotX="12"
+        android:pivotY="12">
+        <path
+            android:fillColor="@color/primary"
+            android:pathData="M12,2C6.48,2 2,6.48 2,12s4.48,10 10,10 10,-4.48 10,-10S17.52,2 12,2zM13,17h-2v-2h2v2zM13,13h-2L11,7h2v6z"/>
+
+    </group>
+</vector>

app/src/main/res/drawable/ic_start.xml

@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="utf-8"?>
 <adaptive-icon xmlns:android="http://schemas.android.com/apk/res/android">
     <background android:drawable="@color/white"/>
-    <foreground android:drawable="@mipmap/ic_start_foreground"/>
+    <foreground android:drawable="@drawable/ic_start_foreground"/>
 </adaptive-icon>

app/src/main/res/drawable/ic_start_foreground.xml

@@ -0,0 +1,19 @@
+<!-- Based off of ic_play_circle_filled_black  -->
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    android:width="108dp"
+    android:height="108dp"
+    android:viewportWidth="36.0"
+    android:viewportHeight="36.0">
+    <group
+        android:translateX="6"
+        android:translateY="6"
+        android:scaleX="0.85"
+        android:scaleY="0.85"
+        android:pivotX="12"
+        android:pivotY="12">
+        <path
+            android:fillColor="@color/primary"
+            android:pathData="M12,2C6.48,2 2,6.48 2,12s4.48,10 10,10 10,-4.48 10,-10S17.52,2 12,2zM10,16.5v-9l6,4.5 -6,4.5z"/>
+
+    </group>
+</vector>

app/src/main/res/drawable/ic_stop.xml

@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="utf-8"?>
 <adaptive-icon xmlns:android="http://schemas.android.com/apk/res/android">
     <background android:drawable="@color/white"/>
-    <foreground android:drawable="@mipmap/ic_stop_foreground"/>
+    <foreground android:drawable="@drawable/ic_stop_foreground"/>
 </adaptive-icon>

app/src/main/res/drawable/ic_stop_foreground.xml

@@ -0,0 +1,18 @@
+<!-- Based off of ic_pause_circle_filled_black icon -->
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    android:width="108dp"
+    android:height="108dp"
+    android:viewportWidth="36.0"
+    android:viewportHeight="36.0">
+    <group
+        android:translateX="6"
+        android:translateY="6"
+        android:scaleX="0.85"
+        android:scaleY="0.85"
+        android:pivotX="12"
+        android:pivotY="12">
+        <path
+            android:fillColor="@color/primary"
+            android:pathData="M12,2C6.48,2 2,6.48 2,12s4.48,10 10,10 10,-4.48 10,-10S17.52,2 12,2zM11,16L9,16L9,8h2v8zM15,16h-2L13,8h2v8z"/>
+    </group>
+</vector>

app/src/main/res/mipmap-anydpi-v26/ic_launcher_round.xml

@@ -1,5 +0,0 @@
-<?xml version="1.0" encoding="utf-8"?>
-<adaptive-icon xmlns:android="http://schemas.android.com/apk/res/android">
-    <background android:drawable="@color/primary"/>
-    <foreground android:drawable="@mipmap/ic_launcher_foreground"/>
-</adaptive-icon>

app/src/main/res/mipmap-anydpi-v26/ic_sos.xml

@@ -1,5 +0,0 @@
-<?xml version="1.0" encoding="utf-8"?>
-<adaptive-icon xmlns:android="http://schemas.android.com/apk/res/android">
-    <background android:drawable="@color/white"/>
-    <foreground android:drawable="@mipmap/ic_sos_foreground"/>
-</adaptive-icon>

app/src/main/res/mipmap-anydpi-v26/ic_sos_round.xml

@@ -1,5 +0,0 @@
-<?xml version="1.0" encoding="utf-8"?>
-<adaptive-icon xmlns:android="http://schemas.android.com/apk/res/android">
-    <background android:drawable="@color/white"/>
-    <foreground android:drawable="@mipmap/ic_sos_foreground"/>
-</adaptive-icon>

app/src/main/res/mipmap-anydpi-v26/ic_stop_round.xml

@@ -1,5 +0,0 @@
-<?xml version="1.0" encoding="utf-8"?>
-<adaptive-icon xmlns:android="http://schemas.android.com/apk/res/android">
-    <background android:drawable="@color/white"/>
-    <foreground android:drawable="@mipmap/ic_stop_foreground"/>
-</adaptive-icon>

app/src/main/res/xml/shortcuts.xml

@@ -7,7 +7,7 @@
     <shortcut
         android:shortcutId="start"
         android:enabled="true"
-        android:icon="@mipmap/ic_start"
+        android:icon="@drawable/ic_start"
         android:shortcutShortLabel="@string/shortcut_start">
         <intent
             android:action="android.intent.action.VIEW"
@@ -22,7 +22,7 @@
     <shortcut
         android:shortcutId="stop"
         android:enabled="true"
-        android:icon="@mipmap/ic_stop"
+        android:icon="@drawable/ic_stop"
         android:shortcutShortLabel="@string/shortcut_stop">
         <intent
             android:action="android.intent.action.VIEW"
@@ -37,7 +37,7 @@
     <shortcut
         android:shortcutId="sos"
         android:enabled="true"
-        android:icon="@mipmap/ic_sos"
+        android:icon="@drawable/ic_sos"
         android:shortcutShortLabel="@string/shortcut_sos">
         <intent
             android:action="android.intent.action.VIEW"