diff --git a/core/src/main/java/org/kiwix/kiwixmobile/core/history/HistoryPresenter.java b/core/src/main/java/org/kiwix/kiwixmobile/core/history/HistoryPresenter.java
deleted file mode 100644
index fe66e6dd1..000000000
--- a/core/src/main/java/org/kiwix/kiwixmobile/core/history/HistoryPresenter.java
+++ /dev/null
@@ -1,133 +0,0 @@
-/*
- * Kiwix Android
- * Copyright (c) 2019 Kiwix <android.kiwix.org>
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program. If not, see <http://www.gnu.org/licenses/>.
- *
- */
-
-package org.kiwix.kiwixmobile.core.history;
-
-import android.util.Log;
-import io.reactivex.CompletableObserver;
-import io.reactivex.Observable;
-import io.reactivex.Scheduler;
-import io.reactivex.SingleObserver;
-import io.reactivex.disposables.Disposable;
-import java.util.ArrayList;
-import java.util.List;
-import javax.inject.Inject;
-import org.kiwix.kiwixmobile.core.base.BasePresenter;
-import org.kiwix.kiwixmobile.core.data.DataSource;
-import org.kiwix.kiwixmobile.core.di.qualifiers.Computation;
-import org.kiwix.kiwixmobile.core.di.qualifiers.MainThread;
-
-class HistoryPresenter extends BasePresenter<HistoryContract.View>
-  implements HistoryContract.Presenter {
-
-  private final DataSource dataSource;
-  private final Scheduler mainThread;
-  private final Scheduler computation;
-  private Disposable disposable;
-
-  @Inject HistoryPresenter(DataSource dataSource, @MainThread Scheduler mainThread,
-    @Computation Scheduler computation) {
-    this.dataSource = dataSource;
-    this.mainThread = mainThread;
-    this.computation = computation;
-  }
-
-  @Override
-  public void loadHistory(boolean showHistoryCurrentBook) {
-    dataSource.getDateCategorizedHistory(showHistoryCurrentBook)
-      .subscribe(new SingleObserver<List<HistoryListItem>>() {
-        @Override
-        public void onSubscribe(Disposable d) {
-          if (disposable != null && !disposable.isDisposed()) {
-            disposable.dispose();
-          }
-          disposable = d;
-          compositeDisposable.add(d);
-        }
-
-        @Override
-        public void onSuccess(List<HistoryListItem> histories) {
-          view.updateHistoryList(histories);
-        }
-
-        @Override
-        public void onError(Throwable e) {
-          Log.e("HistoryPresenter", e.toString());
-        }
-      });
-  }
-
-  @Override
-  public void filterHistory(List<HistoryListItem> historyList, String newText) {
-    Observable.just(historyList)
-      .flatMapIterable(histories -> {
-        List<HistoryListItem> filteredHistories = new ArrayList<>();
-        for (HistoryListItem historyListItem : histories) {
-          if (historyListItem instanceof HistoryListItem.HistoryItem) {
-            final HistoryListItem.HistoryItem historyItem =
-              (HistoryListItem.HistoryItem) historyListItem;
-            if (historyItem.getHistoryTitle().toLowerCase()
-              .contains(newText.toLowerCase())) {
-              filteredHistories.add(historyItem);
-            }
-          }
-        }
-        return filteredHistories;
-      })
-      .toList()
-      .subscribeOn(computation)
-      .observeOn(mainThread)
-      .subscribe(new SingleObserver<List<HistoryListItem>>() {
-        @Override
-        public void onSubscribe(Disposable d) {
-          compositeDisposable.add(d);
-        }
-
-        @Override
-        public void onSuccess(List<HistoryListItem> historyList1) {
-          view.notifyHistoryListFiltered(historyList1);
-        }
-
-        @Override
-        public void onError(Throwable e) {
-          Log.e("HistoryPresenter", e.toString());
-        }
-      });
-  }
-
-  @Override
-  public void deleteHistory(List<HistoryListItem> deleteList) {
-    dataSource.deleteHistory(deleteList)
-      .subscribe(new CompletableObserver() {
-        @Override
-        public void onSubscribe(Disposable d) {
-
-        }
-
-        @Override
-        public void onComplete() {
-
-        }
-
-        @Override
-        public void onError(Throwable e) {
-          Log.e("HistoryPresenter", e.toString());
-        }
-      });
-  }
-}
diff --git a/core/src/main/java/org/kiwix/kiwixmobile/core/history/HistoryPresenter.kt b/core/src/main/java/org/kiwix/kiwixmobile/core/history/HistoryPresenter.kt
new file mode 100644
index 000000000..54b67d8f6
--- /dev/null
+++ b/core/src/main/java/org/kiwix/kiwixmobile/core/history/HistoryPresenter.kt
@@ -0,0 +1,72 @@
+/*
+ * Kiwix Android
+ * Copyright (c) 2019 Kiwix <android.kiwix.org>
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+package org.kiwix.kiwixmobile.core.history
+
+import android.util.Log
+import io.reactivex.Observable
+import io.reactivex.Scheduler
+import io.reactivex.disposables.Disposable
+import org.kiwix.kiwixmobile.core.base.BasePresenter
+import org.kiwix.kiwixmobile.core.data.DataSource
+import org.kiwix.kiwixmobile.core.di.qualifiers.Computation
+import org.kiwix.kiwixmobile.core.di.qualifiers.MainThread
+import org.kiwix.kiwixmobile.core.history.HistoryContract.Presenter
+import org.kiwix.kiwixmobile.core.history.HistoryContract.View
+import org.kiwix.kiwixmobile.core.history.HistoryListItem.HistoryItem
+import javax.inject.Inject
+
+internal class HistoryPresenter @Inject constructor(
+  private val dataSource: DataSource,
+  @param:MainThread private val mainThread: Scheduler,
+  @param:Computation private val computation: Scheduler
+) : BasePresenter<View>(), Presenter {
+  private var disposable: Disposable? = null
+
+  override fun loadHistory(showHistoryCurrentBook: Boolean) {
+    disposable?.takeIf { !it.isDisposed }?.dispose()
+    dataSource.getDateCategorizedHistory(showHistoryCurrentBook)
+      .subscribe(
+        { histories: List<HistoryListItem> -> view?.updateHistoryList(histories) },
+        { e: Throwable -> Log.e("HistoryPresenter", "Failed to load history.", e) }
+    ).let {
+        compositeDisposable.add(it)
+        disposable = it
+      }
+  }
+
+  override fun filterHistory(historyList: List<HistoryListItem>, newText: String) {
+    compositeDisposable.add(Observable.fromCallable {
+        historyList
+          .filterIsInstance<HistoryItem>().filter { item ->
+            item.historyTitle.contains(newText, true)
+          }
+      }
+      .subscribeOn(computation)
+      .observeOn(mainThread)
+      .subscribe(
+        { hList: List<HistoryListItem> -> view?.notifyHistoryListFiltered(hList) },
+        { e: Throwable -> Log.e("HistoryPresenter", "Failed to filter history.", e) }
+      ))
+  }
+
+  override fun deleteHistory(deleteList: List<HistoryListItem>) {
+    dataSource.deleteHistory(deleteList).subscribe({}, { e: Throwable ->
+        Log.e("HistoryPresenter", "Failed to delete history.", e)
+      })
+  }
+}