diff --git a/app/src/main/java/org/transdroid/daemon/Qbittorrent/QbittorrentAdapter.java b/app/src/main/java/org/transdroid/daemon/Qbittorrent/QbittorrentAdapter.java
index 56f8eb4a..a0266f8a 100644
--- a/app/src/main/java/org/transdroid/daemon/Qbittorrent/QbittorrentAdapter.java
+++ b/app/src/main/java/org/transdroid/daemon/Qbittorrent/QbittorrentAdapter.java
@@ -83,18 +83,54 @@ public class QbittorrentAdapter implements IDaemonAdapter {
 
 		try {
 
+			// Since 4.2.0, old API is dropped. Fallback to old one if the new one failed for version <4.2.0
 			// The API version is only supported since qBittorrent 3.2, so otherwise we assume version 1
+
+                        boolean is_v2 = false;
+                        String apiVersionText = "";
+
+                        // First, try the v2 api version endpoint
 			try {
-				String apiVerText = makeRequest(log, "/version/api");
-				apiVersion = Integer.parseInt(apiVerText.trim());
-			} catch (DaemonException | NumberFormatException e) {
-				apiVersion = 1;
-			}
-			log.d(LOG_NAME, "qBittorrent API version is " + apiVersion);
+				apiVersionText = makeRequest(log, "/api/v2/app/webapiVersion");
+                        } catch (DaemonException e) {
+                                // 403 Forbidden - endpoint exists. Keep trying v2
+                                is_v2 = e.getType() == ExceptionType.AuthenticationFailure;
+                        }
+
+                        // Keep trying
+                        if (apiVersion < 0) {
+                                if (is_v2) {
+                                        // Preemptive assumption, for authentication
+                                        apiVersion = 20300; //2.3.0
+
+                                        // Authenticate, and try v2 again
+                                        try {
+                                                ensureAuthenticated(log);
+                                                apiVersionText = makeRequest(log, "/api/v2/app/webapiVersion");
+                                        } catch (DaemonException e) {
+                                                apiVersion = 20300; // assume this is new API 2.3.0 since we are forbidden to access API
+                                        }
+                                } else {
+                                        // Fall back to old api
+                                        try {
+                                                apiVersionText = makeRequest(log, "/version/api");
+                                        } catch (DaemonException e) {
+                                                apiVersion = 1;
+                                        }
+                                }
+                        }
+
+                        if (apiVersion < 0) {
+                                apiVersion = parseVersionNumber(apiVersionText);
+                        }
 
 			// The qBittorent version is only supported since 3.2; for earlier versions we parse the about dialog and parse it
+			// Since 4.2.0, new API version is used instead
 			String versionText = "";
-			if (apiVersion > 1) {
+			if (apiVersion >= 20300) {
+				ensureAuthenticated(log);
+				versionText = makeRequest(log, "/api/v2/app/version").substring(1);
+			} else if (apiVersion > 10000) {
 				// Format is something like 'v3.2.0'
 				versionText = makeRequest(log, "/version/qbittorrent").substring(1);
 			} else {
@@ -109,44 +145,49 @@ public class QbittorrentAdapter implements IDaemonAdapter {
 				}
 			}
 
-			// String found: now parse a version like 2.9.7 as a number like 20907 (allowing 10 places for each .)
-			String[] parts = versionText.split("\\.");
-			if (parts.length > 0) {
-				version = Integer.parseInt(parts[0]) * 100 * 100;
-				if (parts.length > 1) {
-					version += Integer.parseInt(parts[1]) * 100;
-					if (parts.length > 2) {
-						// For the last part only read until a non-numeric character is read
-						// For example version 3.0.0-alpha5 is read as version code 30000
-						String numbers = "";
-						for (char c : parts[2].toCharArray()) {
-							if (Character.isDigit(c))
-								// Still a number; add it to the numbers string
-								numbers += Character.toString(c);
-							else {
-								// No longer reading numbers; stop reading
-								break;
-							}
-						}
-						version += Integer.parseInt(numbers);
-						return;
-					}
-				}
-			}
+                        version = parseVersionNumber(versionText);
 
 		} catch (Exception e) {
 			// Unable to establish version number; assume an old version by setting it to version 1
 			version = 10000;
-			apiVersion = 1;
+			apiVersion = 10000;
 		}
 
 	}
 
+        private int parseVersionNumber(String versionText) {
+                // String found: now parse a version like 2.9.7 as a number like 20907 (allowing 10 places for each .)
+                int version = -1;
+                String[] parts = versionText.split("\\.");
+                if (parts.length > 0) {
+                        version = Integer.parseInt(parts[0]) * 100 * 100;
+                        if (parts.length > 1) {
+                                version += Float.parseFloat(parts[1]) * 100;
+                                if (parts.length > 2) {
+                                        // For the last part only read until a non-numeric character is read
+                                        // For example version 3.0.0-alpha5 is read as version code 30000
+                                        String numbers = "";
+                                        for (char c : parts[2].toCharArray()) {
+                                                if (Character.isDigit(c))
+                                                        // Still a number; add it to the numbers string
+                                                        numbers += Character.toString(c);
+                                                else {
+                                                        // No longer reading numbers; stop reading
+                                                        break;
+                                                }
+                                        }
+                                        version += Float.parseFloat(numbers);
+                                }
+                        }
+                }
+                return version;
+        }
+
 	private synchronized void ensureAuthenticated(Log log) throws DaemonException {
 		// API changed in 3.2.0, login is now handled by its own request, which provides you a cookie.
 		// If we don't have that cookie, let's try and get it.
 
-		if (apiVersion < 2) {
+		if (apiVersion < 20000) {
 			return;
 		}
 
@@ -159,8 +200,13 @@ public class QbittorrentAdapter implements IDaemonAdapter {
 			}
 		}
 
-		makeRequest(log, "/login", new BasicNameValuePair("username", settings.getUsername()),
-				new BasicNameValuePair("password", settings.getPassword()));
+		if (apiVersion >= 20300) {
+			makeRequest(log, "/api/v2/auth/login", new BasicNameValuePair("username", settings.getUsername()),
+					new BasicNameValuePair("password", settings.getPassword()));
+		} else {
+			makeRequest(log, "/login", new BasicNameValuePair("username", settings.getUsername()),
+					new BasicNameValuePair("password", settings.getPassword()));
+		}
 		// The HttpClient will automatically remember the cookie for us, no need to parse it out.
 
 		// However, we would like to see if authentication was successful or not... 
@@ -185,8 +231,12 @@ public class QbittorrentAdapter implements IDaemonAdapter {
 
 			switch (task.getMethod()) {
 				case Retrieve:
+
+					// Request all torrents from server
 					String path;
-					if (version >= 30200) {
+					if (version >= 40200) {
+						path = "/api/v2/torrents/info";
+					} else if (version >= 30200) {
 						path = "/query/torrents";
 					} else if (version >= 30000) {
 						path = "/json/torrents";
@@ -194,78 +244,145 @@ public class QbittorrentAdapter implements IDaemonAdapter {
 						path = "/json/events";
 					}
 
-					// Request all torrents from server
 					JSONArray result = new JSONArray(makeRequest(log, path));
+
 					return new RetrieveTaskSuccessResult((RetrieveTask) task, parseJsonTorrents(result), parseJsonLabels(result));
 
 				case GetTorrentDetails:
 
 					// Request tracker and error details for a specific teacher
 					String mhash = task.getTargetTorrent().getUniqueID();
-					JSONArray messages =
-							new JSONArray(makeRequest(log, (version >= 30200 ? "/query/propertiesTrackers/" : "/json/propertiesTrackers/") + mhash));
-					JSONArray pieces = new JSONArray(makeRequest(log, "/query/getPieceStates/" + mhash));
+					JSONArray messages;
+					JSONArray pieces;
+					if (version >= 40200) {
+						messages = new JSONArray(makeRequest(log, "/api/v2/torrents/trackers", new BasicNameValuePair("hash", mhash)));
+						pieces = new JSONArray(makeRequest(log, "/api/v2/torrents/pieceStates",  new BasicNameValuePair("hash", mhash)));
+					} else {
+						messages = new JSONArray(makeRequest(log, "/query/propertiesTrackers/" + mhash));
+						pieces = new JSONArray(makeRequest(log, "/query/getPieceStates/" + mhash));
+					}
+
 					return new GetTorrentDetailsTaskSuccessResult((GetTorrentDetailsTask) task, parseJsonTorrentDetails(messages, pieces));
 
 				case GetFileList:
 
 					// Request files listing for a specific torrent
 					String fhash = task.getTargetTorrent().getUniqueID();
-					JSONArray files =
-							new JSONArray(makeRequest(log, (version >= 30200 ? "/query/propertiesFiles/" : "/json/propertiesFiles/") + fhash));
+					JSONArray files;
+					if (version >= 40200) {
+						files = new JSONArray(makeRequest(log, "/api/v2/torrents/files", new BasicNameValuePair("hash", fhash)));
+					} else if (version >= 30200) {
+						files = new JSONArray(makeRequest(log, "/query/propertiesFiles/" + fhash));
+					} else {
+						files = new JSONArray(makeRequest(log, "/json/propertiesFiles/" + fhash));
+					}
+
 					return new GetFileListTaskSuccessResult((GetFileListTask) task, parseJsonFiles(files));
 
 				case AddByFile:
 
 					// Upload a local .torrent file
+					if (version >= 40200) {
+						path = "/api/v2/torrents/add";
+					} else {
+						path = "/command/upload";
+					}
+
 					String ufile = ((AddByFileTask) task).getFile();
-					makeUploadRequest("/command/upload", ufile, log);
+					makeUploadRequest(path, ufile, log);
 					return new DaemonTaskSuccessResult(task);
 
 				case AddByUrl:
 
 					// Request to add a torrent by URL
 					String url = ((AddByUrlTask) task).getUrl();
-					makeRequest(log, "/command/download", new BasicNameValuePair("urls", url));
+					if (version >= 40200) {
+						path = "/api/v2/torrents/add";
+					} else {
+						path = "/command/upload";
+					}
+
+					makeRequest(log, path, new BasicNameValuePair("urls", url));
 					return new DaemonTaskSuccessResult(task);
 
 				case AddByMagnetUrl:
 
 					// Request to add a magnet link by URL
 					String magnet = ((AddByMagnetUrlTask) task).getUrl();
-					makeRequest(log, "/command/download", new BasicNameValuePair("urls", magnet));
+					if (version >= 40200) {
+						path = "/api/v2/torrents/add";
+					} else {
+						path = "/command/download";
+					}
+
+					makeRequest(log, path, new BasicNameValuePair("urls", magnet));
 					return new DaemonTaskSuccessResult(task);
 
 				case Remove:
 
 					// Remove a torrent
 					RemoveTask removeTask = (RemoveTask) task;
-					makeRequest(log, (removeTask.includingData() ? "/command/deletePerm" : "/command/delete"),
-							new BasicNameValuePair("hashes", removeTask.getTargetTorrent().getUniqueID()));
+					if (version >= 40200) {
+						if (removeTask.includingData()) {
+							makeRequest(log, "/api/v2/torrents/delete",
+									new BasicNameValuePair("hashes", removeTask.getTargetTorrent().getUniqueID()),
+									new BasicNameValuePair("deleteFiles", "true"));
+						} else {
+							makeRequest(log, "/api/v2/torrents/delete",
+									new BasicNameValuePair("hashes", removeTask.getTargetTorrent().getUniqueID()),
+									new BasicNameValuePair("deleteFiles", "false"));
+						}
+
+					} else {
+						path = (removeTask.includingData() ? "/command/deletePerm" : "/command/delete");
+						makeRequest(log, path, new BasicNameValuePair("hashes", removeTask.getTargetTorrent().getUniqueID()));
+					}
+
 					return new DaemonTaskSuccessResult(task);
 
 				case Pause:
 
 					// Pause a torrent
-					makeRequest(log, "/command/pause", new BasicNameValuePair("hash", task.getTargetTorrent().getUniqueID()));
+					if (version >= 40200) {
+						makeRequest(log, "/api/v2/torrents/pause", new BasicNameValuePair("hashes", task.getTargetTorrent().getUniqueID()));
+					} else {
+						makeRequest(log, "/command/pause", new BasicNameValuePair("hash", task.getTargetTorrent().getUniqueID()));
+					}
+
 					return new DaemonTaskSuccessResult(task);
 
 				case PauseAll:
 
 					// Resume all torrents
-					makeRequest(log, "/command/pauseall");
+					if (version >= 40200) {
+						makeRequest(log, "/api/v2/torrents/pause", new BasicNameValuePair("hashes", "all"));
+					} else {
+						makeRequest(log, "/command/pauseall");
+					}
+
 					return new DaemonTaskSuccessResult(task);
 
 				case Resume:
 
 					// Resume a torrent
-					makeRequest(log, "/command/resume", new BasicNameValuePair("hash", task.getTargetTorrent().getUniqueID()));
+					if (version >= 40200) {
+						makeRequest(log, "/api/v2/torrents/resume", new BasicNameValuePair("hashes", task.getTargetTorrent().getUniqueID()));
+					} else {
+						makeRequest(log, "/command/resume", new BasicNameValuePair("hash", task.getTargetTorrent().getUniqueID()));
+					}
+
 					return new DaemonTaskSuccessResult(task);
 
 				case ResumeAll:
 
 					// Resume all torrents
-					makeRequest(log, "/command/resumeall");
+					if (version >= 40200) {
+						path = "/api/v2/torrents/resume";
+						makeRequest(log, path, new BasicNameValuePair("hashes", "all"));
+					} else {
+						makeRequest(log, "/command/resumeall");
+					}
+
 					return new DaemonTaskSuccessResult(task);
 
 				case SetFilePriorities:
@@ -282,33 +399,59 @@ public class QbittorrentAdapter implements IDaemonAdapter {
 					}
 					// We have to make a separate request per file, it seems
 					for (TorrentFile file : setPrio.getForFiles()) {
-						makeRequest(log, "/command/setFilePrio", new BasicNameValuePair("hash", task.getTargetTorrent().getUniqueID()),
+						if (version >= 40200) {
+							path = "/api/v2/torrents/filePrio";
+						} else {
+							path = "/command/setFilePrio";
+						}
+						makeRequest(log, path, new BasicNameValuePair("hash", task.getTargetTorrent().getUniqueID()),
 								new BasicNameValuePair("id", file.getKey()), new BasicNameValuePair("priority", newPrio));
+
 					}
 					return new DaemonTaskSuccessResult(task);
 
-                                case ForceRecheck:
+				case ForceRecheck:
 
-                                        // Force recheck a torrent
-                                        makeRequest(log, "/command/recheck", new BasicNameValuePair("hash", task.getTargetTorrent().getUniqueID()));
-                                        return new DaemonTaskSuccessResult(task);
+						// Force recheck a torrent
+					if (version >= 40200) {
+						path = "/api/v2/torrents/recheck";
+					} else {
+						path = "/command/recheck";
+					}
+					makeRequest(log, path, new BasicNameValuePair("hashes", task.getTargetTorrent().getUniqueID()));
+					return new DaemonTaskSuccessResult(task);
 
-                                case ToggleSequentialDownload:
+				case ToggleSequentialDownload:
 
-                                        // Toggle sequential download mode on a torrent
-                                        makeRequest(log, "/command/toggleSequentialDownload", new BasicNameValuePair("hashes", task.getTargetTorrent().getUniqueID()));
-                                        return new DaemonTaskSuccessResult(task);
+					// Toggle sequential download mode on a torrent
+					if (version >= 40200) {
+						path = "/api/v2/torrents/toggleSequentialDownload";
+					} else {
+						path = "/command/toggleSequentialDownload";
+					}
+					makeRequest(log, path, new BasicNameValuePair("hashes", task.getTargetTorrent().getUniqueID()));
+					return new DaemonTaskSuccessResult(task);
 
-                                case ToggleFirstLastPieceDownload:
+				case ToggleFirstLastPieceDownload:
 
-                                        // Set policy for downloading first and last piece first on a torrent
-                                        makeRequest(log, "/command/toggleFirstLastPiecePrio", new BasicNameValuePair("hashes", task.getTargetTorrent().getUniqueID()));
-                                        return new DaemonTaskSuccessResult(task);
+					// Set policy for downloading first and last piece first on a torrent
+					if (version >= 40200) {
+						path = "/api/v2/torrents/toggleFirstLastPiecePrio";
+					} else {
+						path = "/command/toggleFirstLastPiecePrio";
+					}
+					makeRequest(log, path, new BasicNameValuePair("hashes", task.getTargetTorrent().getUniqueID()));
+					return new DaemonTaskSuccessResult(task);
 
 				case SetLabel:
 
 					SetLabelTask labelTask = (SetLabelTask) task;
-					makeRequest(log, "/command/setCategory",
+					if (version >= 40200) {
+						path = "/api/v2/torrents/setCategory";
+					} else {
+						path = "/command/setCategory";
+					}
+					makeRequest(log, path,
 							new BasicNameValuePair("hashes", task.getTargetTorrent().getUniqueID()),
 							new BasicNameValuePair("category", labelTask.getNewLabel()));
 					return new DaemonTaskSuccessResult(task);
@@ -316,7 +459,12 @@ public class QbittorrentAdapter implements IDaemonAdapter {
 				case SetDownloadLocation:
 
 					SetDownloadLocationTask setLocationTask = (SetDownloadLocationTask) task;
-					makeRequest(log, "/command/setLocation",
+					if (version >= 40200) {
+						path = "/api/v2/torrents/setLocation";
+					} else {
+						path = "/command/setLocation";
+					}
+					makeRequest(log, path,
 							new BasicNameValuePair("hashes", task.getTargetTorrent().getUniqueID()),
 							new BasicNameValuePair("location", setLocationTask.getNewLocation()));
 					return new DaemonTaskSuccessResult(task);
@@ -324,18 +472,33 @@ public class QbittorrentAdapter implements IDaemonAdapter {
 				case SetTransferRates:
 
 					// Request to set the maximum transfer rates
+					String pathDL;
+					String pathUL;
 					SetTransferRatesTask ratesTask = (SetTransferRatesTask) task;
 					String dl = (ratesTask.getDownloadRate() == null ? "NaN" : Long.toString(ratesTask.getDownloadRate() * 1024));
 					String ul = (ratesTask.getUploadRate() == null ? "NaN" : Long.toString(ratesTask.getUploadRate() * 1024));
 
-					makeRequest(log, "/command/setGlobalDlLimit", new BasicNameValuePair("limit", dl));
-					makeRequest(log, "/command/setGlobalUpLimit", new BasicNameValuePair("limit", ul));
+					if (version >= 40200) {
+						pathDL = "/api/v2/torrents/setDownloadLimit";
+						pathUL = "/api/v2/torrents/setUploadLimit";
+					} else {
+						pathDL = "/command/setGlobalDlLimit";
+						pathUL = "/command/setGlobalUpLimit";
+					}
+
+					makeRequest(log, pathDL, new BasicNameValuePair("limit", dl));
+					makeRequest(log, pathUL, new BasicNameValuePair("limit", ul));
 					return new DaemonTaskSuccessResult(task);
 
 				case GetStats:
 
 					// Refresh alternative download speeds setting
-					JSONObject stats = new JSONObject(makeRequest(log, "/sync/maindata?rid=0"));
+					if (version >= 40200) {
+						path = "/api/v2/sync/maindata?rid=0";
+					} else {
+						path = "/sync/maindata?rid=0";
+					}
+					JSONObject stats = new JSONObject(makeRequest(log, path));
 					JSONObject serverStats = stats.optJSONObject("server_state");
 					boolean alternativeSpeeds = false;
 					if (serverStats != null) {
@@ -346,7 +509,12 @@ public class QbittorrentAdapter implements IDaemonAdapter {
 				case SetAlternativeMode:
 
 					// Flip alternative speed mode
-					makeRequest(log, "/command/toggleAlternativeSpeedLimits");
+					if (version >= 40200) {
+						path = "/api/v2/transfer/toggleSpeedLimitsMode";
+					} else {
+						path = "/command/toggleAlternativeSpeedLimits";
+					}
+					makeRequest(log, path);
 					return new DaemonTaskSuccessResult(task);
 
 				default:
@@ -365,7 +533,9 @@ public class QbittorrentAdapter implements IDaemonAdapter {
 		try {
 
 			// Setup request using POST
-			HttpPost httppost = new HttpPost(buildWebUIUrl(path));
+			String url_to_request = buildWebUIUrl(path);
+			HttpPost httppost = new HttpPost(url_to_request);
+			
 			List<NameValuePair> nvps = new ArrayList<>();
 			Collections.addAll(nvps, params);
 			httppost.setEntity(new UrlEncodedFormEntity(nvps, HTTP.UTF_8));
@@ -406,6 +576,11 @@ public class QbittorrentAdapter implements IDaemonAdapter {
 			// Execute
 			HttpResponse response = httpclient.execute(httppost);
 
+                        // Throw exception on 403
+                        if (response.getStatusLine().getStatusCode() == 403) {
+                                throw new DaemonException(ExceptionType.AuthenticationFailure, "Response code 403");
+                        }
+
 			HttpEntity entity = response.getEntity();
 			if (entity != null) {
 
@@ -426,7 +601,13 @@ public class QbittorrentAdapter implements IDaemonAdapter {
 
 		} catch (Exception e) {
 			log.d(LOG_NAME, "Error: " + e.toString());
-			throw new DaemonException(ExceptionType.ConnectionError, e.toString());
+
+                        if (e instanceof DaemonException) {
+                                throw (DaemonException) e;
+                        }
+                        else {
+			        throw new DaemonException(ExceptionType.ConnectionError, e.toString());
+                        }
 		}
 
 	}
@@ -486,7 +667,7 @@ public class QbittorrentAdapter implements IDaemonAdapter {
 		Map<String, Label> labels = new HashMap<>();
 		for (int i = 0; i < response.length(); i++) {
 			JSONObject tor = response.getJSONObject(i);
-			if (apiVersion >= 2) {
+			if (apiVersion >= 20000) {
 				String label = tor.optString("category");
 				if (label != null && label.length() > 0) {
 					final Label labelObject = labels.get(label);
@@ -518,7 +699,7 @@ public class QbittorrentAdapter implements IDaemonAdapter {
 			Date completionOn = null;
 			String label = null;
 
-			if (apiVersion >= 2) {
+			if (apiVersion >= 20000) {
 				leechers = new int[2];
 				leechers[0] = tor.getInt("num_leechs");
 				leechers[1] = tor.getInt("num_complete") + tor.getInt("num_incomplete");
@@ -710,7 +891,7 @@ public class QbittorrentAdapter implements IDaemonAdapter {
 			JSONObject file = response.getJSONObject(i);
 
 			long size;
-			if (apiVersion >= 2) {
+			if (apiVersion >= 20000) {
 				size = file.getLong("size");
 			} else {
 				size = parseSize(file.getString("size"));