diff --git a/build.gradle b/build.gradle
index e75ef0e..5a76904 100644
--- a/build.gradle
+++ b/build.gradle
@@ -1,5 +1,5 @@
 group 'de.tbressler.waterrower'
-version '0.9.7'
+version '0.9.8'
 
 apply plugin: 'java'
 apply plugin: 'maven'
diff --git a/src/main/java/de/tbressler/waterrower/subscriptions/AbstractMemorySubscription.java b/src/main/java/de/tbressler/waterrower/subscriptions/AbstractMemorySubscription.java
index c9b2db2..73af0b5 100644
--- a/src/main/java/de/tbressler/waterrower/subscriptions/AbstractMemorySubscription.java
+++ b/src/main/java/de/tbressler/waterrower/subscriptions/AbstractMemorySubscription.java
@@ -31,7 +31,7 @@ abstract class AbstractMemorySubscription implements ISubscription {
      * @param memory Single, double or triple memory. Must not be null.
      * @param location The memory location, must not be null.
      */
-    AbstractMemorySubscription(Memory memory, MemoryLocation location) {
+    public AbstractMemorySubscription(Memory memory, MemoryLocation location) {
         this.memory = requireNonNull(memory);
         this.location = requireNonNull(location);
     }
@@ -64,6 +64,6 @@ public final void handle(AbstractMessage msg) {
      *
      * @param msg The message, never null.
      */
-    abstract void handle(DataMemoryMessage msg);
+    abstract protected void handle(DataMemoryMessage msg);
 
 }
diff --git a/src/main/java/de/tbressler/waterrower/subscriptions/AverageStrokeTimeSubscription.java b/src/main/java/de/tbressler/waterrower/subscriptions/AverageStrokeTimeSubscription.java
index 6c1029b..e4a8a96 100644
--- a/src/main/java/de/tbressler/waterrower/subscriptions/AverageStrokeTimeSubscription.java
+++ b/src/main/java/de/tbressler/waterrower/subscriptions/AverageStrokeTimeSubscription.java
@@ -74,6 +74,6 @@ protected final void handle(DataMemoryMessage msg) {
      *
      * @param averageStrokeTime The new average stroke time.
      */
-    protected abstract void onAverageStrokeTimeUpdated(int averageStrokeTime);
+    abstract protected void onAverageStrokeTimeUpdated(int averageStrokeTime);
 
 }
diff --git a/src/main/java/de/tbressler/waterrower/subscriptions/ClockCountDownSubscription.java b/src/main/java/de/tbressler/waterrower/subscriptions/ClockCountDownSubscription.java
index e2784c9..8af1f48 100644
--- a/src/main/java/de/tbressler/waterrower/subscriptions/ClockCountDownSubscription.java
+++ b/src/main/java/de/tbressler/waterrower/subscriptions/ClockCountDownSubscription.java
@@ -51,6 +51,6 @@ protected final void handle(DataMemoryMessage msg) {
      *
      * @param duration The new clock count-down, never null.
      */
-    protected abstract void onClockCountDownUpdated(Duration duration);
+    abstract protected void onClockCountDownUpdated(Duration duration);
 
 }
diff --git a/src/main/java/de/tbressler/waterrower/subscriptions/DisplayedDurationSubscription.java b/src/main/java/de/tbressler/waterrower/subscriptions/DisplayedDurationSubscription.java
index 7b38ae6..71312d0 100644
--- a/src/main/java/de/tbressler/waterrower/subscriptions/DisplayedDurationSubscription.java
+++ b/src/main/java/de/tbressler/waterrower/subscriptions/DisplayedDurationSubscription.java
@@ -51,6 +51,6 @@ protected final void handle(DataMemoryMessage msg) {
      *
      * @param duration The new duration, never null.
      */
-    protected abstract void onDurationUpdated(Duration duration);
+    abstract protected void onDurationUpdated(Duration duration);
 
 }
diff --git a/src/main/java/de/tbressler/waterrower/subscriptions/DistanceSubscription.java b/src/main/java/de/tbressler/waterrower/subscriptions/DistanceSubscription.java
index 87bbf49..c5f585b 100644
--- a/src/main/java/de/tbressler/waterrower/subscriptions/DistanceSubscription.java
+++ b/src/main/java/de/tbressler/waterrower/subscriptions/DistanceSubscription.java
@@ -91,6 +91,6 @@ protected final void handle(DataMemoryMessage msg) {
      * @param mode The distance mode (e.g. total distance or displayed distance), never null.
      * @param distance The new distance.
      */
-    protected abstract void onDistanceUpdated(DistanceMode mode, int distance);
+    abstract protected void onDistanceUpdated(DistanceMode mode, int distance);
 
 }
diff --git a/src/main/java/de/tbressler/waterrower/subscriptions/IntensitySubscription.java b/src/main/java/de/tbressler/waterrower/subscriptions/IntensitySubscription.java
index 1c1d922..62f303f 100644
--- a/src/main/java/de/tbressler/waterrower/subscriptions/IntensitySubscription.java
+++ b/src/main/java/de/tbressler/waterrower/subscriptions/IntensitySubscription.java
@@ -63,7 +63,7 @@ private static MemoryLocation getMemoryLocation(IntensityType intensityType) {
 
 
     @Override
-    void handle(DataMemoryMessage msg) {
+    protected void handle(DataMemoryMessage msg) {
         int intensity = intFromHighAndLow(msg.getValue2(), msg.getValue1());
 
         // If the received intensity is the same as before,
@@ -83,6 +83,6 @@ void handle(DataMemoryMessage msg) {
      * @param intensityType The intensity type, never null.
      * @param intensity The new value.
      */
-    abstract void onIntensityUpdated(IntensityType intensityType, int intensity);
+    abstract protected void onIntensityUpdated(IntensityType intensityType, int intensity);
 
 }
diff --git a/src/main/java/de/tbressler/waterrower/subscriptions/PulseCountSubscription.java b/src/main/java/de/tbressler/waterrower/subscriptions/PulseCountSubscription.java
index 8db58cf..b4e19aa 100644
--- a/src/main/java/de/tbressler/waterrower/subscriptions/PulseCountSubscription.java
+++ b/src/main/java/de/tbressler/waterrower/subscriptions/PulseCountSubscription.java
@@ -32,6 +32,6 @@ public final void handle(AbstractMessage msg) {
      *
      * @param pulsesCount The number of pulse’s counted during the last 25mS period.
      */
-    abstract void onPulseCount(int pulsesCount);
+    abstract protected void onPulseCount(int pulsesCount);
 
 }
\ No newline at end of file
diff --git a/src/main/java/de/tbressler/waterrower/subscriptions/StrokeCountSubscription.java b/src/main/java/de/tbressler/waterrower/subscriptions/StrokeCountSubscription.java
index 744f310..5236ef0 100644
--- a/src/main/java/de/tbressler/waterrower/subscriptions/StrokeCountSubscription.java
+++ b/src/main/java/de/tbressler/waterrower/subscriptions/StrokeCountSubscription.java
@@ -47,6 +47,6 @@ protected final void handle(DataMemoryMessage msg) {
      *
      * @param strokes The new stroke count.
      */
-    protected abstract void onStrokeCountUpdated(int strokes);
+    abstract protected void onStrokeCountUpdated(int strokes);
 
 }
diff --git a/src/main/java/de/tbressler/waterrower/subscriptions/StrokeSubscription.java b/src/main/java/de/tbressler/waterrower/subscriptions/StrokeSubscription.java
index 2da1d6e..f9e76b8 100644
--- a/src/main/java/de/tbressler/waterrower/subscriptions/StrokeSubscription.java
+++ b/src/main/java/de/tbressler/waterrower/subscriptions/StrokeSubscription.java
@@ -38,6 +38,6 @@ public final void handle(AbstractMessage msg) {
      *
      * @param strokeType The type of stroke (e.g. start or end), never null.
      */
-    abstract void onStroke(StrokeType strokeType);
+    abstract protected void onStroke(StrokeType strokeType);
 
 }
diff --git a/src/main/java/de/tbressler/waterrower/subscriptions/TankVolumeSubscription.java b/src/main/java/de/tbressler/waterrower/subscriptions/TankVolumeSubscription.java
index bdfa0d7..53cbc61 100644
--- a/src/main/java/de/tbressler/waterrower/subscriptions/TankVolumeSubscription.java
+++ b/src/main/java/de/tbressler/waterrower/subscriptions/TankVolumeSubscription.java
@@ -43,6 +43,6 @@ protected final void handle(DataMemoryMessage msg) {
      *
      * @param tankVolume The volume of water in the tank (in liters).
      */
-    protected abstract void onTankVolumeUpdated(int tankVolume);
+    abstract protected void onTankVolumeUpdated(int tankVolume);
 
 }
diff --git a/src/main/java/de/tbressler/waterrower/subscriptions/WorkoutFlagsSubscription.java b/src/main/java/de/tbressler/waterrower/subscriptions/WorkoutFlagsSubscription.java
index 6679819..1a89edb 100644
--- a/src/main/java/de/tbressler/waterrower/subscriptions/WorkoutFlagsSubscription.java
+++ b/src/main/java/de/tbressler/waterrower/subscriptions/WorkoutFlagsSubscription.java
@@ -57,6 +57,6 @@ public final void handle(DataMemoryMessage msg) {
      *
      * @param flags The flags of the workout mode, never null.
      */
-    protected abstract void onWorkoutModeUpdated(WorkoutFlags flags);
+    abstract protected void onWorkoutModeUpdated(WorkoutFlags flags);
 
 }
diff --git a/src/main/java/de/tbressler/waterrower/subscriptions/WorkoutIntervalSubscription.java b/src/main/java/de/tbressler/waterrower/subscriptions/WorkoutIntervalSubscription.java
index 3fd674a..9cd2125 100644
--- a/src/main/java/de/tbressler/waterrower/subscriptions/WorkoutIntervalSubscription.java
+++ b/src/main/java/de/tbressler/waterrower/subscriptions/WorkoutIntervalSubscription.java
@@ -106,6 +106,6 @@ protected final void handle(DataMemoryMessage msg) {
      * @param intervalIndex The index of the workout interval.
      * @param value The new value.
      */
-    protected abstract void onWorkoutIntervalUpdated(IntervalType intervalType, int intervalIndex, int value);
+    abstract protected void onWorkoutIntervalUpdated(IntervalType intervalType, int intervalIndex, int value);
 
 }
diff --git a/src/main/java/de/tbressler/waterrower/subscriptions/WorkoutTotalSubscription.java b/src/main/java/de/tbressler/waterrower/subscriptions/WorkoutTotalSubscription.java
index b25fb21..60fa00e 100644
--- a/src/main/java/de/tbressler/waterrower/subscriptions/WorkoutTotalSubscription.java
+++ b/src/main/java/de/tbressler/waterrower/subscriptions/WorkoutTotalSubscription.java
@@ -70,7 +70,7 @@ private static MemoryLocation getMemoryLocation(ValueType valueType) {
 
 
     @Override
-    void handle(DataMemoryMessage msg) {
+    protected void handle(DataMemoryMessage msg) {
         int value = intFromHighAndLow(msg.getValue2(), msg.getValue1());
 
         // If the received value is the same as before,
@@ -90,6 +90,6 @@ void handle(DataMemoryMessage msg) {
      * @param valueType The value type, never null.
      * @param value The new value.
      */
-    abstract void onTotalWorkoutValueUpdated(ValueType valueType, int value);
+    abstract protected void onTotalWorkoutValueUpdated(ValueType valueType, int value);
 
 }
diff --git a/src/test/java/de/tbressler/waterrower/subscriptions/TestAbstractMemorySubscription.java b/src/test/java/de/tbressler/waterrower/subscriptions/TestAbstractMemorySubscription.java
index 748085d..314cb0e 100644
--- a/src/test/java/de/tbressler/waterrower/subscriptions/TestAbstractMemorySubscription.java
+++ b/src/test/java/de/tbressler/waterrower/subscriptions/TestAbstractMemorySubscription.java
@@ -116,7 +116,7 @@ public void handle_withOtherLocationMessage_doesntNotifiesInternalHandler() {
     private AbstractMemorySubscription newAbstractMemorySubscription(Memory memory, MemoryLocation location) {
         return new AbstractMemorySubscription(memory, location) {
             @Override
-            void handle(DataMemoryMessage msg) {
+            protected void handle(DataMemoryMessage msg) {
                 internalSubscription.handle(msg);
             }
         };
diff --git a/src/test/java/de/tbressler/waterrower/subscriptions/TestDebugSubscription.java b/src/test/java/de/tbressler/waterrower/subscriptions/TestDebugSubscription.java
index 06f3991..d5de05b 100644
--- a/src/test/java/de/tbressler/waterrower/subscriptions/TestDebugSubscription.java
+++ b/src/test/java/de/tbressler/waterrower/subscriptions/TestDebugSubscription.java
@@ -25,7 +25,7 @@ public class TestDebugSubscription {
     public void new_withNullMemory_throwsNPE() {
         new DebugSubscription(null, CLOCK_DOWN_DEC) {
             @Override
-            void handle(DataMemoryMessage msg) {}
+            protected void handle(DataMemoryMessage msg) {}
         };
     }
 
@@ -33,7 +33,7 @@ void handle(DataMemoryMessage msg) {}
     public void new_withNullMemoryLocation_throwsNPE() {
         new DebugSubscription(SINGLE_MEMORY, null) {
             @Override
-            void handle(DataMemoryMessage msg) {}
+            protected void handle(DataMemoryMessage msg) {}
         };
     }
 
@@ -43,7 +43,7 @@ void handle(DataMemoryMessage msg) {}
     public void poll_returnsMessageForConstructorValues() {
         DebugSubscription subscription = new DebugSubscription(DOUBLE_MEMORY, M_S_LOW_AVERAGE) {
             @Override
-            void handle(DataMemoryMessage msg) {}
+            protected void handle(DataMemoryMessage msg) {}
         };
 
         ReadMemoryMessage msg = (ReadMemoryMessage) subscription.poll();
diff --git a/src/test/java/de/tbressler/waterrower/subscriptions/TestIntensitySubscription.java b/src/test/java/de/tbressler/waterrower/subscriptions/TestIntensitySubscription.java
index 57227a6..0557e34 100644
--- a/src/test/java/de/tbressler/waterrower/subscriptions/TestIntensitySubscription.java
+++ b/src/test/java/de/tbressler/waterrower/subscriptions/TestIntensitySubscription.java
@@ -34,7 +34,7 @@ public class TestIntensitySubscription {
     public void new_withNull_throwsNPE() {
         new IntensitySubscription(null) {
             @Override
-            void onIntensityUpdated(IntensityType intensityType, int intensity) {}
+            protected void onIntensityUpdated(IntensityType intensityType, int intensity) {}
         };
     }
 
@@ -106,7 +106,7 @@ public void handle_withOtherMessage_doesntNotifyOnAverageStrokeTimeUpdate() {
     private IntensitySubscription newIntensitySubscription(IntensityType type) {
         return new IntensitySubscription(type) {
             @Override
-            void onIntensityUpdated(IntensityType intensityType, int intensity) {
+            protected void onIntensityUpdated(IntensityType intensityType, int intensity) {
                 internalSubscription.onIntensityUpdated(intensityType, intensity);
             }
         };
diff --git a/src/test/java/de/tbressler/waterrower/subscriptions/TestPulseCountSubscription.java b/src/test/java/de/tbressler/waterrower/subscriptions/TestPulseCountSubscription.java
index 357fe41..29e4357 100644
--- a/src/test/java/de/tbressler/waterrower/subscriptions/TestPulseCountSubscription.java
+++ b/src/test/java/de/tbressler/waterrower/subscriptions/TestPulseCountSubscription.java
@@ -27,7 +27,7 @@ public class TestPulseCountSubscription {
     public void setUp() {
         subscription = new PulseCountSubscription() {
             @Override
-            void onPulseCount(int pulsesCount) {
+            protected void onPulseCount(int pulsesCount) {
                 internalSubscription.onPulseCount(pulsesCount);
             }
         };
diff --git a/src/test/java/de/tbressler/waterrower/subscriptions/TestStrokeSubscription.java b/src/test/java/de/tbressler/waterrower/subscriptions/TestStrokeSubscription.java
index 06b2fa2..6eb19bb 100644
--- a/src/test/java/de/tbressler/waterrower/subscriptions/TestStrokeSubscription.java
+++ b/src/test/java/de/tbressler/waterrower/subscriptions/TestStrokeSubscription.java
@@ -30,7 +30,7 @@ public class TestStrokeSubscription {
     public void setUp() {
         subscription = new StrokeSubscription() {
             @Override
-            void onStroke(StrokeType strokeType) {
+            protected void onStroke(StrokeType strokeType) {
                 internalSubscription.onStroke(strokeType);
             }
         };
diff --git a/src/test/java/de/tbressler/waterrower/subscriptions/TestWorkoutTotalSubscription.java b/src/test/java/de/tbressler/waterrower/subscriptions/TestWorkoutTotalSubscription.java
index 7f87b12..18573b2 100644
--- a/src/test/java/de/tbressler/waterrower/subscriptions/TestWorkoutTotalSubscription.java
+++ b/src/test/java/de/tbressler/waterrower/subscriptions/TestWorkoutTotalSubscription.java
@@ -106,7 +106,7 @@ public void handle_for2DifferentMessages_notifiesTwice() {
     private WorkoutTotalSubscription newWorkoutTotalSubscription(ValueType valueType) {
         return new WorkoutTotalSubscription(valueType) {
             @Override
-            void onTotalWorkoutValueUpdated(ValueType valueType, int value) {
+            protected void onTotalWorkoutValueUpdated(ValueType valueType, int value) {
                 internalSubscription.onTotalWorkoutValueUpdated(valueType, value);
             }
         };