diff --git a/app/src/androidTest/java/de/test/antennapod/util/event/FeedItemEventListener.java b/app/src/androidTest/java/de/test/antennapod/util/event/FeedItemEventListener.java
deleted file mode 100644
index 7e8fc1205..000000000
--- a/app/src/androidTest/java/de/test/antennapod/util/event/FeedItemEventListener.java
+++ /dev/null
@@ -1,46 +0,0 @@
-package de.test.antennapod.util.event;
-
-import androidx.annotation.NonNull;
-
-import org.greenrobot.eventbus.EventBus;
-import org.greenrobot.eventbus.Subscribe;
-
-import java.util.ArrayList;
-import java.util.List;
-
-import de.danoeh.antennapod.event.FeedItemEvent;
-import io.reactivex.functions.Consumer;
-
-/**
- * Test helpers to listen {@link FeedItemEvent} and handle them accordingly
- *
- */
-public class FeedItemEventListener {
-    private final List<FeedItemEvent> events = new ArrayList<>();
-
-    /**
-     * Provides an listener subscribing to {@link FeedItemEvent} that the callers can use
-     *
-     * Note: it uses RxJava's version of {@link Consumer} because it allows exceptions to be thrown.
-     */
-    public static void withFeedItemEventListener(@NonNull Consumer<FeedItemEventListener> consumer)
-            throws Exception {
-        FeedItemEventListener feedItemEventListener = new FeedItemEventListener();
-        try {
-            EventBus.getDefault().register(feedItemEventListener);
-            consumer.accept(feedItemEventListener);
-        } finally {
-            EventBus.getDefault().unregister(feedItemEventListener);
-        }
-    }
-
-    @Subscribe
-    public void onEvent(FeedItemEvent event) {
-        events.add(event);
-    }
-
-    @NonNull
-    public List<? extends FeedItemEvent> getEvents() {
-        return events;
-    }
-}
diff --git a/app/src/main/java/de/danoeh/antennapod/adapter/CoverLoader.java b/app/src/main/java/de/danoeh/antennapod/adapter/CoverLoader.java
index d5c67c675..c87228cdd 100644
--- a/app/src/main/java/de/danoeh/antennapod/adapter/CoverLoader.java
+++ b/app/src/main/java/de/danoeh/antennapod/adapter/CoverLoader.java
@@ -11,7 +11,6 @@ import com.bumptech.glide.RequestBuilder;
 import com.bumptech.glide.request.RequestOptions;
 import com.bumptech.glide.request.target.CustomViewTarget;
 import com.bumptech.glide.request.transition.Transition;
-import de.danoeh.antennapod.activity.MainActivity;
 
 import java.lang.ref.WeakReference;
 
@@ -21,11 +20,9 @@ public class CoverLoader {
     private String fallbackUri;
     private ImageView imgvCover;
     private boolean textAndImageCombined;
-    private MainActivity activity;
     private TextView fallbackTitle;
 
-    public CoverLoader(MainActivity activity) {
-        this.activity = activity;
+    public CoverLoader() {
     }
 
     public CoverLoader withUri(String uri) {
diff --git a/app/src/main/java/de/danoeh/antennapod/adapter/SubscriptionsRecyclerAdapter.java b/app/src/main/java/de/danoeh/antennapod/adapter/SubscriptionsRecyclerAdapter.java
index 284f3e468..2961796c6 100644
--- a/app/src/main/java/de/danoeh/antennapod/adapter/SubscriptionsRecyclerAdapter.java
+++ b/app/src/main/java/de/danoeh/antennapod/adapter/SubscriptionsRecyclerAdapter.java
@@ -244,7 +244,7 @@ public class SubscriptionsRecyclerAdapter extends SelectableAdapter<Subscription
                 count.setVisibility(View.GONE);
             }
 
-            CoverLoader coverLoader = new CoverLoader(mainActivityRef.get());
+            CoverLoader coverLoader = new CoverLoader();
             boolean textAndImageCombined;
             if (drawerItem.type == NavDrawerData.DrawerItem.Type.FEED) {
                 Feed feed = ((NavDrawerData.FeedDrawerItem) drawerItem).feed;
diff --git a/app/src/main/java/de/danoeh/antennapod/view/viewholder/EpisodeItemViewHolder.java b/app/src/main/java/de/danoeh/antennapod/view/viewholder/EpisodeItemViewHolder.java
index 01d4a10f0..fe9b55a2e 100644
--- a/app/src/main/java/de/danoeh/antennapod/view/viewholder/EpisodeItemViewHolder.java
+++ b/app/src/main/java/de/danoeh/antennapod/view/viewholder/EpisodeItemViewHolder.java
@@ -129,7 +129,7 @@ public class EpisodeItemViewHolder extends RecyclerView.ViewHolder {
         }
 
         if (coverHolder.getVisibility() == View.VISIBLE) {
-            new CoverLoader(activity)
+            new CoverLoader()
                     .withUri(ImageResourceUtils.getEpisodeListImageLocation(item))
                     .withFallbackUri(item.getFeed().getImageUrl())
                     .withPlaceholderView(placeholder)
@@ -225,7 +225,7 @@ public class EpisodeItemViewHolder extends RecyclerView.ViewHolder {
         itemView.setBackgroundResource(ThemeUtils.getDrawableFromAttr(activity, R.attr.selectableItemBackground));
         placeholder.setText("");
         if (coverHolder.getVisibility() == View.VISIBLE) {
-            new CoverLoader(activity)
+            new CoverLoader()
                     .withResource(R.color.medium_gray)
                     .withPlaceholderView(placeholder)
                     .withCoverView(cover)
diff --git a/app/src/main/java/de/danoeh/antennapod/view/viewholder/HorizontalItemViewHolder.java b/app/src/main/java/de/danoeh/antennapod/view/viewholder/HorizontalItemViewHolder.java
index 21a29a920..8d44f419e 100644
--- a/app/src/main/java/de/danoeh/antennapod/view/viewholder/HorizontalItemViewHolder.java
+++ b/app/src/main/java/de/danoeh/antennapod/view/viewholder/HorizontalItemViewHolder.java
@@ -58,7 +58,7 @@ public class HorizontalItemViewHolder extends RecyclerView.ViewHolder {
         card.setAlpha(1.0f);
         float density = activity.getResources().getDisplayMetrics().density;
         card.setCardBackgroundColor(SurfaceColors.getColorForElevation(activity, 1 * density));
-        new CoverLoader(activity)
+        new CoverLoader()
                 .withUri(ImageResourceUtils.getEpisodeListImageLocation(item))
                 .withFallbackUri(item.getFeed().getImageUrl())
                 .withCoverView(cover)
@@ -102,7 +102,7 @@ public class HorizontalItemViewHolder extends RecyclerView.ViewHolder {
 
     public void bindDummy() {
         card.setAlpha(0.1f);
-        new CoverLoader(activity)
+        new CoverLoader()
                 .withResource(android.R.color.transparent)
                 .withCoverView(cover)
                 .load();
diff --git a/core/src/main/java/de/danoeh/antennapod/core/service/playback/ExoPlayerWrapper.java b/core/src/main/java/de/danoeh/antennapod/core/service/playback/ExoPlayerWrapper.java
index 8ee47a147..48bbc3321 100644
--- a/core/src/main/java/de/danoeh/antennapod/core/service/playback/ExoPlayerWrapper.java
+++ b/core/src/main/java/de/danoeh/antennapod/core/service/playback/ExoPlayerWrapper.java
@@ -66,7 +66,6 @@ public class ExoPlayerWrapper {
     public static final int BUFFERING_STARTED = -1;
     public static final int BUFFERING_ENDED = -2;
     private static final String TAG = "ExoPlayerWrapper";
-    public static final int ERROR_CODE_OFFSET = 1000;
 
     private final Context context;
     private final Disposable bufferingUpdateDisposable;
diff --git a/core/src/main/java/de/danoeh/antennapod/core/util/download/ConnectionStateMonitor.java b/core/src/main/java/de/danoeh/antennapod/core/util/download/ConnectionStateMonitor.java
deleted file mode 100644
index a8d9437ee..000000000
--- a/core/src/main/java/de/danoeh/antennapod/core/util/download/ConnectionStateMonitor.java
+++ /dev/null
@@ -1,41 +0,0 @@
-package de.danoeh.antennapod.core.util.download;
-
-import android.content.Context;
-import android.net.ConnectivityManager;
-import android.net.NetworkCapabilities;
-import android.net.NetworkRequest;
-import android.util.Log;
-
-public class ConnectionStateMonitor
-        extends ConnectivityManager.NetworkCallback
-        implements ConnectivityManager.OnNetworkActiveListener {
-    private static final String TAG = "ConnectionStateMonitor";
-    final NetworkRequest networkRequest;
-
-    public ConnectionStateMonitor() {
-        networkRequest = new NetworkRequest.Builder()
-                .addTransportType(NetworkCapabilities.TRANSPORT_CELLULAR)
-                .addTransportType(NetworkCapabilities.TRANSPORT_WIFI)
-                .build();
-    }
-
-    @Override
-    public void onNetworkActive() {
-        Log.d(TAG, "ConnectionStateMonitor::onNetworkActive network connection changed");
-        NetworkConnectionChangeHandler.networkChangedDetected();
-    }
-
-    public void enable(Context context) {
-        ConnectivityManager connectivityManager =
-                (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
-        connectivityManager.registerNetworkCallback(networkRequest, this);
-        connectivityManager.addDefaultNetworkActiveListener(this);
-    }
-
-    public void disable(Context context) {
-        ConnectivityManager connectivityManager =
-                (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
-        connectivityManager.unregisterNetworkCallback(this);
-        connectivityManager.removeDefaultNetworkActiveListener(this);
-    }
-}
\ No newline at end of file
diff --git a/core/src/main/java/de/danoeh/antennapod/core/util/playback/MediaPlayerError.java b/core/src/main/java/de/danoeh/antennapod/core/util/playback/MediaPlayerError.java
deleted file mode 100644
index 8ca8bbf6c..000000000
--- a/core/src/main/java/de/danoeh/antennapod/core/util/playback/MediaPlayerError.java
+++ /dev/null
@@ -1,36 +0,0 @@
-package de.danoeh.antennapod.core.util.playback;
-
-import android.content.Context;
-import android.media.MediaPlayer;
-import com.google.android.exoplayer2.ExoPlaybackException;
-import de.danoeh.antennapod.core.R;
-import de.danoeh.antennapod.core.service.playback.ExoPlayerWrapper;
-
-/** Utility class for MediaPlayer errors. */
-public class MediaPlayerError {
-    private MediaPlayerError(){}
-
-    /** Get a human-readable string for a specific error code. */
-    public static String getErrorString(Context context, int code) {
-        int resId;
-        switch (code) {
-            case MediaPlayer.MEDIA_ERROR_SERVER_DIED:
-                resId = R.string.playback_error_server_died;
-                break;
-            case MediaPlayer.MEDIA_ERROR_UNSUPPORTED: // fall-through
-            case ExoPlayerWrapper.ERROR_CODE_OFFSET + ExoPlaybackException.TYPE_RENDERER:
-                resId = R.string.playback_error_unsupported;
-                break;
-            case MediaPlayer.MEDIA_ERROR_TIMED_OUT:
-                resId = R.string.playback_error_timeout;
-                break;
-            case ExoPlayerWrapper.ERROR_CODE_OFFSET + ExoPlaybackException.TYPE_SOURCE:
-                resId = R.string.playback_error_source;
-                break;
-            default:
-                resId = R.string.playback_error_unknown;
-                break;
-        }
-        return context.getString(resId) + " (" + code + ")";
-    }
-}
diff --git a/core/src/test/java/android/text/TextUtils.java b/core/src/test/java/android/text/TextUtils.java
index eda31c3b5..709cb9e93 100644
--- a/core/src/test/java/android/text/TextUtils.java
+++ b/core/src/test/java/android/text/TextUtils.java
@@ -13,6 +13,7 @@ public class TextUtils {
      * @param b second CharSequence to check
      * @return true if a and b are equal
      */
+    @SuppressWarnings("unused")
     public static boolean equals(CharSequence a, CharSequence b) {
         if (a == b) return true;
         int length;
diff --git a/core/src/test/java/de/danoeh/antennapod/core/storage/DbTasksTest.java b/core/src/test/java/de/danoeh/antennapod/core/storage/DbTasksTest.java
index 6a7e51bac..3eed90ea8 100644
--- a/core/src/test/java/de/danoeh/antennapod/core/storage/DbTasksTest.java
+++ b/core/src/test/java/de/danoeh/antennapod/core/storage/DbTasksTest.java
@@ -252,25 +252,4 @@ public class DbTasksTest {
             lastDate = item.getPubDate();
         }
     }
-
-    private Feed createSavedFeed(String title, int numFeedItems) {
-        final Feed feed = new Feed("url", null, title);
-
-        if (numFeedItems > 0) {
-            List<FeedItem> items = new ArrayList<>(numFeedItems);
-            for (int i = 1; i <= numFeedItems; i++) {
-                FeedItem item = new FeedItem(0, "item " + i + " of " + title, "id" + title + i, "link",
-                        new Date(), FeedItem.UNPLAYED, feed);
-                items.add(item);
-            }
-            feed.setItems(items);
-        }
-
-        PodDBAdapter adapter = PodDBAdapter.getInstance();
-        adapter.open();
-        adapter.setCompleteFeed(feed);
-        adapter.close();
-        return feed;
-    }
-
 }
diff --git a/model/src/main/java/de/danoeh/antennapod/model/feed/FeedItem.java b/model/src/main/java/de/danoeh/antennapod/model/feed/FeedItem.java
index e078d755a..25ea9330c 100644
--- a/model/src/main/java/de/danoeh/antennapod/model/feed/FeedItem.java
+++ b/model/src/main/java/de/danoeh/antennapod/model/feed/FeedItem.java
@@ -333,10 +333,6 @@ public class FeedItem implements Serializable {
         }
     }
 
-    public enum State {
-        UNREAD, IN_PROGRESS, READ, PLAYING
-    }
-
     public long getFeedId() {
         return feedId;
     }
diff --git a/model/src/main/java/de/danoeh/antennapod/model/feed/SortOrder.java b/model/src/main/java/de/danoeh/antennapod/model/feed/SortOrder.java
index 08504b445..f6c90341a 100644
--- a/model/src/main/java/de/danoeh/antennapod/model/feed/SortOrder.java
+++ b/model/src/main/java/de/danoeh/antennapod/model/feed/SortOrder.java
@@ -72,12 +72,4 @@ public enum SortOrder {
     public static String toCodeString(@Nullable SortOrder sortOrder) {
         return sortOrder != null ? Integer.toString(sortOrder.code) : null;
     }
-
-    public static SortOrder[] valuesOf(String[] stringValues) {
-        SortOrder[] values = new SortOrder[stringValues.length];
-        for (int i = 0; i < stringValues.length; i++) {
-            values[i] = SortOrder.valueOf(stringValues[i]);
-        }
-        return values;
-    }
 }
diff --git a/net/sync/gpoddernet/src/main/java/de/danoeh/antennapod/net/sync/gpoddernet/GpodnetService.java b/net/sync/gpoddernet/src/main/java/de/danoeh/antennapod/net/sync/gpoddernet/GpodnetService.java
index 7873ae4fe..da23cd351 100644
--- a/net/sync/gpoddernet/src/main/java/de/danoeh/antennapod/net/sync/gpoddernet/GpodnetService.java
+++ b/net/sync/gpoddernet/src/main/java/de/danoeh/antennapod/net/sync/gpoddernet/GpodnetService.java
@@ -166,38 +166,6 @@ public class GpodnetService implements ISyncService {
         }
     }
 
-    /**
-     * Uploads the subscriptions of a specific device.
-     * <p/>
-     * This method requires authentication.
-     *
-     * @param deviceId      The ID of the device whose subscriptions should be updated.
-     * @param subscriptions A list of feed URLs containing all subscriptions of the
-     *                      device.
-     * @throws IllegalArgumentException              If username, deviceId or subscriptions is null.
-     * @throws GpodnetServiceAuthenticationException If there is an authentication error.
-     */
-    public void uploadSubscriptions(@NonNull String deviceId, @NonNull List<String> subscriptions)
-            throws GpodnetServiceException {
-        requireLoggedIn();
-        try {
-            URL url = new URI(baseScheme, null, baseHost, basePort,
-                    String.format("/subscriptions/%s/%s.txt", username, deviceId), null, null).toURL();
-            StringBuilder builder = new StringBuilder();
-            for (String s : subscriptions) {
-                builder.append(s);
-                builder.append("\n");
-            }
-            RequestBody body = RequestBody.create(TEXT, builder.toString());
-            Request.Builder request = new Request.Builder().put(body).url(url);
-            executeRequest(request);
-        } catch (MalformedURLException | URISyntaxException e) {
-            e.printStackTrace();
-            throw new GpodnetServiceException(e);
-        }
-
-    }
-
     /**
      * Updates the subscription list of a specific device.
      * <p/>
diff --git a/ui/common/src/main/java/de/danoeh/antennapod/ui/common/PagedToolbarFragment.java b/ui/common/src/main/java/de/danoeh/antennapod/ui/common/PagedToolbarFragment.java
index 3d82cb32c..48793ff13 100644
--- a/ui/common/src/main/java/de/danoeh/antennapod/ui/common/PagedToolbarFragment.java
+++ b/ui/common/src/main/java/de/danoeh/antennapod/ui/common/PagedToolbarFragment.java
@@ -1,6 +1,5 @@
 package de.danoeh.antennapod.ui.common;
 
-import androidx.annotation.NonNull;
 import com.google.android.material.appbar.MaterialToolbar;
 import androidx.fragment.app.Fragment;
 import androidx.viewpager2.widget.ViewPager2;
@@ -10,23 +9,8 @@ import androidx.viewpager2.widget.ViewPager2;
  * All items share the same general menu items and are just allowed to show/hide them.
  */
 public abstract class PagedToolbarFragment extends Fragment {
-    private MaterialToolbar toolbar;
-    private ViewPager2 viewPager;
 
-    /**
-     * Invalidate the toolbar menu if the current child fragment is visible.
-     * @param child The fragment to invalidate
-     */
-    public void invalidateOptionsMenuIfActive(@NonNull Fragment child) {
-        Fragment visibleChild = getChildFragmentManager().findFragmentByTag("f" + viewPager.getCurrentItem());
-        if (visibleChild == child) {
-            visibleChild.onPrepareOptionsMenu(toolbar.getMenu());
-        }
-    }
-
-    protected void setupPagedToolbar(MaterialToolbar toolbar, ViewPager2 viewPager) {
-        this.toolbar = toolbar;
-        this.viewPager = viewPager;
+    protected void setupPagedToolbar(final MaterialToolbar toolbar, final ViewPager2 viewPager) {
 
         toolbar.setOnMenuItemClickListener(item -> {
             if (this.onOptionsItemSelected(item)) {
diff --git a/ui/i18n/src/main/res/values/strings.xml b/ui/i18n/src/main/res/values/strings.xml
index 03044a79d..1ce509002 100644
--- a/ui/i18n/src/main/res/values/strings.xml
+++ b/ui/i18n/src/main/res/values/strings.xml
@@ -320,11 +320,6 @@
 
     <!-- Mediaplayer messages -->
     <string name="playback_error_generic"><![CDATA[The media file could not be played.\n\n- Try deleting and re-downloading the episode.\n- Check your network connection, and make sure no VPN or login page is blocking access.\n- Try long-pressing and sharing the \"Media address\" to your web browser to see if it can be played there. If not, contact the podcast creators.]]></string>
-    <string name="playback_error_server_died">Server died</string>
-    <string name="playback_error_unsupported">Unsupported media type</string>
-    <string name="playback_error_timeout">Operation timed out</string>
-    <string name="playback_error_source">Unable to access media file</string>
-    <string name="playback_error_unknown">Unknown error</string>
     <string name="no_media_playing_label">No media playing</string>
     <string name="position_default_label" translatable="false">00:00:00</string>
     <string name="unknown_media_key">AntennaPod - Unknown media key: %1$d</string>