diff --git a/AndroidManifest.xml b/AndroidManifest.xml
index 15b3785f8..36454bcf1 100644
--- a/AndroidManifest.xml
+++ b/AndroidManifest.xml
@@ -2,8 +2,8 @@
 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
     xmlns:tools="http://schemas.android.com/tools"
     package="jmri.enginedriver"
-    android:versionCode="60"
-    android:versionName="2.21.60" android:installLocation="auto">
+    android:versionCode="61"
+    android:versionName="2.21.61" android:installLocation="auto">
     <uses-permission android:name="android.permission.INTERNET" />
     <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
     <uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
diff --git a/assets/about_page.html b/assets/about_page.html
index 261f49a5e..8407f391c 100644
--- a/assets/about_page.html
+++ b/assets/about_page.html
@@ -18,7 +18,9 @@ <h1>Engine Driver Throttle for Android</h1>
 <p><b>Latest changes for this version include:</b></p>
 <ul>
     <li>remove turnout hardware list, WiThrottle Server changing to handle numeric-only</li>
+    <li>changes to EngineDriver icon</li>
     <li>German translations by Al Babinsky and Daniel Sieber</li>
+    <li>prevent crashes reported to Play Store</li>
 </ul>
 <p><em><a
         href="https://raw.githubusercontent.com/JMRI/EngineDriver/master/changelog-and-todo-list.txt"
diff --git a/changelog-and-todo-list.txt b/changelog-and-todo-list.txt
index b93c977e2..932eafa82 100644
--- a/changelog-and-todo-list.txt
+++ b/changelog-and-todo-list.txt
@@ -1,5 +1,7 @@
 **Version 2.21
  * remove turnout hardware list, WiThrottle Server changed to also handle numeric-only
+ * changes to EngineDriver icon
+ * prevent crashes reported to Play Store
 **Version 2.20
  * Fix for Gamepad functions F10 and above
  * monochrome icon for the notification bar
@@ -403,7 +405,6 @@
  * turnouts
  *   TODO: add turnouts to list as used, when no list available
  *   TODO: combine loco control and turnout control in one page
- *   TODO: list available "system" based on items in use, maybe with dropdown on Turnout
  *   TODO: pref to sort by system name vs. user name
  *   TODO: use PTT titles for Turnouts/Turnout
  * connection
@@ -420,6 +421,7 @@
  *   TODO: check for error on send and do something with it 
  *   TODO: redo hard-coded 29 in function arrays (29 is hard-coded in WiT side, so no rush)
  * throttle:
+ *   TODO: manually create roster entries (function labels) and store on device
  *   TODO: if nS is lead of ED consist, MT-nS loses track of "other" loco (test with a "partial steal")
  *   TODO: clear loco buttons on reconnect attempt until actual MT+ received
  *   TODO: make Stop "sticky" and ignore slider unless direction is selected
@@ -436,7 +438,6 @@
  *   TODO: disconnect connections made by roster stuff
  *   TODO: add close button and roster image to details dialog
  *   TODO: simplify select_loco by removing handler
- *   TODO: manually create roster entries and store on device
  *   TODO: for "auto" handle the Digitrax numbering, i.e. 1-128 is short
  *   TODO: allow user to delete individual recents (long-press?)
  * preferences:
diff --git a/src/jmri/enginedriver/threaded_application.java b/src/jmri/enginedriver/threaded_application.java
index 8428738ab..7e9738d9c 100644
--- a/src/jmri/enginedriver/threaded_application.java
+++ b/src/jmri/enginedriver/threaded_application.java
@@ -125,7 +125,7 @@ public class threaded_application extends Application {
     String[] rt_user_names;
     String[] rt_states;
     HashMap<String, String> rt_state_names; //if not set, routes are not allowed
-    HashMap<String, String> roster_entries;  //roster sent by WiThrottle
+    LinkedHashMap<String, String> roster_entries;  //roster sent by WiThrottle
     LinkedHashMap<String, String> consist_entries;
     private static DownloadRosterTask dlRosterTask = null;
     private static DownloadMetaTask dlMetadataTask = null;
@@ -1019,7 +1019,7 @@ private void process_roster_function_string(String response_str, int whichThrott
         //  RL2]\[NS2591}|{2591}|{L]\[NS4805}|{4805}|{L
         private void process_roster_list(String response_str) {
             //clear the global variable
-            roster_entries = new HashMap<>();
+            roster_entries = new LinkedHashMap<>();
 
             String[] ta = splitByString(response_str, "]\\[");  //initial separation
             //initialize app arrays (skipping first)
@@ -2066,7 +2066,7 @@ private void initShared() {
 
         consist_entries = new LinkedHashMap<>();
         roster = null;
-        roster_entries = null;
+        roster_entries = new LinkedHashMap<>();
         metadata = null;
         doFinish = false;
         turnouts_list_position = 0;
diff --git a/src/jmri/enginedriver/throttle.java b/src/jmri/enginedriver/throttle.java
index 13b729bd9..bcc3c8ac1 100644
--- a/src/jmri/enginedriver/throttle.java
+++ b/src/jmri/enginedriver/throttle.java
@@ -1703,8 +1703,8 @@ void applySpeedRelatedOptions(int whichThrottle) {
 
     void enable_disable_buttons(int whichThrottle, boolean forceDisable) {
         boolean newEnabledState = false;
-            if (!forceDisable) {
-                newEnabledState = mainapp.consists[whichThrottle].isActive();      // set false if lead loco is not assigned
+            if (!forceDisable && (whichThrottle < mainapp.consists.length)) { // avoid index crash, but may simply push to next line
+                newEnabledState = mainapp.consists[whichThrottle].isActive(); // set false if lead loco is not assigned
             }
             bFwds[whichThrottle].setEnabled(newEnabledState);
             bRevs[whichThrottle].setEnabled(newEnabledState);
@@ -3805,13 +3805,12 @@ public void onPageFinished(WebView view, String url) {
         for (int throttleIndex = 0; throttleIndex < mainapp.maxThrottles; throttleIndex++) {
             changeTimers[throttleIndex] = new ChangeDelay(throttleIndex);
         }
-
         // tone generator for feedback sounds
         try {
             tg = new ToneGenerator(AudioManager.STREAM_NOTIFICATION,
                 preferences.getIntPrefValue(prefs,"prefGamePadFeedbackVolume", getApplicationContext().getResources().getString(R.string.prefGamePadFeedbackVolumeDefaultValue)));
         } catch (RuntimeException e) {
-            Log.d("Engine_Driver", "new ToneGenerateor failed. Runtime Exception, OS " + android.os.Build.VERSION.SDK_INT + " Message: " + e);
+            Log.e("Engine_Driver", "new ToneGenerator failed. Runtime Exception, OS " + android.os.Build.VERSION.SDK_INT + " Message: " + e);
         }
         // set GamePad Support
         setGamepadKeys();
@@ -4120,7 +4119,9 @@ void set_function_labels_and_listeners_for_view(int whichThrottle) {
                 // while we are using it (causing issues during button update below)
                 function_labels_temp = mainapp.function_labels_default;
                 if (!prefAlwaysUseDefaultFunctionLabels) {
-                    if (mainapp.function_labels[whichThrottle] != null && mainapp.function_labels[whichThrottle].size() > 0) {
+                    if (mainapp.function_labels != null
+                            && mainapp.function_labels[whichThrottle] != null
+                            && mainapp.function_labels[whichThrottle].size() > 0) {
                         function_labels_temp = new LinkedHashMap<>(mainapp.function_labels[whichThrottle]);
                     } else {
                         if (!mainapp.consists[whichThrottle].isLeadFromRoster()) {
@@ -4528,7 +4529,7 @@ protected void onActivityResult(int requestCode, int resultCode, Intent data) {
                             tg = new ToneGenerator(AudioManager.STREAM_NOTIFICATION,
                                 preferences.getIntPrefValue(prefs, "prefGamePadFeedbackVolume", getApplicationContext().getResources().getString(R.string.prefGamePadFeedbackVolumeDefaultValue)));
                         } catch (RuntimeException e) {
-                            Log.d("Engine_Driver", "new ToneGenerateor failed. Runtime Exception, OS " + android.os.Build.VERSION.SDK_INT + " Message: " + e);
+                            Log.e("Engine_Driver", "new ToneGenerator failed. Runtime Exception, OS " + android.os.Build.VERSION.SDK_INT + " Message: " + e);
                         }
                     }
                     // update GamePad Support