diff --git a/app/src/main/java/io/bartek/ttsserver/preference/Preference.kt b/app/src/main/java/io/bartek/ttsserver/preference/Preference.kt
index 50b85d8..f55f07e 100644
--- a/app/src/main/java/io/bartek/ttsserver/preference/Preference.kt
+++ b/app/src/main/java/io/bartek/ttsserver/preference/Preference.kt
@@ -7,4 +7,5 @@ object PreferenceKey {
    const val ENABLE_WAVE_ENDPOINT = "preference_enable_wave_endpoint"
    const val ENABLE_SONOS_ENDPOINT = "preference_enable_sonos_endpoint"
    const val TTS = "preference_tts"
+   const val INVALIDATE_SONOS_CACHE = "preference_invalidate_sonos_cache"
 }
\ No newline at end of file
diff --git a/app/src/main/java/io/bartek/ttsserver/preference/PreferencesFragment.kt b/app/src/main/java/io/bartek/ttsserver/preference/PreferencesFragment.kt
index ab6fe7f..b29b39f 100644
--- a/app/src/main/java/io/bartek/ttsserver/preference/PreferencesFragment.kt
+++ b/app/src/main/java/io/bartek/ttsserver/preference/PreferencesFragment.kt
@@ -6,6 +6,7 @@ import android.content.Intent
 import android.content.IntentFilter
 import android.os.Bundle
 import android.text.InputType
+import android.widget.Toast
 import androidx.localbroadcastmanager.content.LocalBroadcastManager
 import androidx.preference.Preference
 import androidx.preference.PreferenceFragmentCompat
@@ -19,6 +20,7 @@ class PreferencesFragment : PreferenceFragmentCompat() {
    private lateinit var sayEndpointPreference: SwitchPreference
    private lateinit var waveEndpointPreference: SwitchPreference
    private lateinit var ttsEnginePreference: Preference
+   private lateinit var clearSonosCachePreference: Preference
 
    private val receiver = object : BroadcastReceiver() {
       override fun onReceive(context: Context?, intent: Intent?) {
@@ -35,14 +37,14 @@ class PreferencesFragment : PreferenceFragmentCompat() {
    override fun onResume() {
       super.onResume()
       LocalBroadcastManager
-         .getInstance(context!!)
+         .getInstance(requireContext())
          .registerReceiver(receiver, IntentFilter(ForegroundService.CHANGE_STATE))
       updateViewAccordingToServiceState(ForegroundService.state)
    }
 
    override fun onPause() {
       LocalBroadcastManager
-         .getInstance(context!!)
+         .getInstance(requireContext())
          .unregisterReceiver(receiver)
       super.onPause()
    }
@@ -58,6 +60,12 @@ class PreferencesFragment : PreferenceFragmentCompat() {
          startActivity(Intent(ANDROID_TTS_SETTINGS))
          true
       }
+      clearSonosCachePreference = findPreference(PreferenceKey.INVALIDATE_SONOS_CACHE)!!
+      clearSonosCachePreference.setOnPreferenceClickListener {
+         context?.cacheDir?.listFiles() ?. forEach { it.delete() }
+         Toast.makeText(context, getString(R.string.preference_invalidate_sonos_cache_toast), Toast.LENGTH_SHORT).show()
+         true
+      }
       updateViewAccordingToServiceState(ForegroundService.state)
    }
 
diff --git a/app/src/main/res/values/strings.xml b/app/src/main/res/values/strings.xml
index 8b83820..908dbf4 100644
--- a/app/src/main/res/values/strings.xml
+++ b/app/src/main/res/values/strings.xml
@@ -25,8 +25,13 @@
     <string name="preference_enable_sonos_endpoint_title">Enable /sonos endpoint</string>
     <string name="preference_tts_summary">Go to platform\'s TTS engine settings and adjust its parameters</string>
     <string name="preference_tts_title">TTS engine settings</string>
+    <string name="preference_invalidate_sonos_cache_summary">Clear application cache directory from already generated Sonos TTS data for given sentences. You typically want to do it when you change the TTS engine\'s voice settings.</string>
+    <string name="preference_invalidate_sonos_cache_title">Invalidate Sonos cache</string>
     <string name="preference_category_tts">TTS engine</string>
     <string name="preference_category_server">Server</string>
+    <string name="preference_category_sonos">Sonos</string>
+    <string name="preference_invalidate_sonos_cache_toast">Sonos cache has been invalidated</string>
+
     <string name="menu_settings">Settings</string>
     <string name="menu_help">Help</string>
 </resources>
diff --git a/app/src/main/res/xml/preferences.xml b/app/src/main/res/xml/preferences.xml
index 5ed76fd..e951f3f 100644
--- a/app/src/main/res/xml/preferences.xml
+++ b/app/src/main/res/xml/preferences.xml
@@ -41,5 +41,13 @@
             app:iconSpaceReserved="false" />
     </PreferenceCategory>
 
+    <PreferenceCategory android:title="@string/preference_category_sonos" app:iconSpaceReserved="false">
+        <Preference
+            android:key="preference_invalidate_sonos_cache"
+            android:summary="@string/preference_invalidate_sonos_cache_summary"
+            app:title="@string/preference_invalidate_sonos_cache_title"
+            app:iconSpaceReserved="false" />
+    </PreferenceCategory>
+
 
 </androidx.preference.PreferenceScreen>
\ No newline at end of file