diff --git a/app/src/androidTest/java/at/bitfire/davdroid/ui/setup/DavResourceFinderTest.java b/app/src/androidTest/java/at/bitfire/davdroid/ui/setup/DavResourceFinderTest.java
index 806cd803..2db8fd8a 100644
--- a/app/src/androidTest/java/at/bitfire/davdroid/ui/setup/DavResourceFinderTest.java
+++ b/app/src/androidTest/java/at/bitfire/davdroid/ui/setup/DavResourceFinderTest.java
@@ -53,11 +53,11 @@ public class DavResourceFinderTest extends InstrumentationTestCase {
         server.setDispatcher(new TestDispatcher());
         server.start();
 
-        credentials = new LoginCredentials(URI.create("/"), "mock", "12345", true);
+        credentials = new LoginCredentials(URI.create("/"), "mock", "12345");
         finder = new DavResourceFinder(getInstrumentation().getContext(), credentials);
 
         client = HttpClient.create();
-        client = HttpClient.addAuthentication(client, credentials.userName, credentials.password, credentials.authPreemptive);
+        client = HttpClient.addAuthentication(client, credentials.userName, credentials.password);
     }
 
     @Override
@@ -129,8 +129,11 @@ public class DavResourceFinderTest extends InstrumentationTestCase {
 
         @Override
         public MockResponse dispatch(RecordedRequest rq) throws InterruptedException {
-            if (!checkAuth(rq))
-                return new MockResponse().setResponseCode(401);
+            if (!checkAuth(rq)) {
+                MockResponse authenticate = new MockResponse().setResponseCode(401);
+                authenticate.setHeader("WWW-Authenticate", "Basic realm=\"test\"");
+                return authenticate;
+            }
 
             String path = rq.getPath();
 
diff --git a/app/src/main/java/at/bitfire/davdroid/AccountSettings.java b/app/src/main/java/at/bitfire/davdroid/AccountSettings.java
index 6cd99e59..2a006403 100644
--- a/app/src/main/java/at/bitfire/davdroid/AccountSettings.java
+++ b/app/src/main/java/at/bitfire/davdroid/AccountSettings.java
@@ -60,7 +60,6 @@ public class AccountSettings {
             KEY_SETTINGS_VERSION = "version",
 
             KEY_USERNAME = "user_name",
-            KEY_AUTH_PREEMPTIVE = "auth_preemptive",
 
             KEY_WIFI_ONLY = "wifi_only",            // sync on WiFi only (default: false)
             KEY_WIFI_ONLY_SSID = "wifi_only_ssid";  // restrict sync to specific WiFi SSID
@@ -147,11 +146,10 @@ public class AccountSettings {
         }
     }
 
-    public static Bundle initialUserData(String userName, boolean preemptive) {
+    public static Bundle initialUserData(String userName) {
         Bundle bundle = new Bundle();
         bundle.putString(KEY_SETTINGS_VERSION, String.valueOf(CURRENT_VERSION));
         bundle.putString(KEY_USERNAME, userName);
-        bundle.putString(KEY_AUTH_PREEMPTIVE, Boolean.toString(preemptive));
         return bundle;
     }
 
@@ -164,9 +162,6 @@ public class AccountSettings {
     public String password() { return accountManager.getPassword(account); }
     public void password(@NonNull String password) { accountManager.setPassword(account, password); }
 
-    public boolean preemptiveAuth() { return Boolean.parseBoolean(accountManager.getUserData(account, KEY_AUTH_PREEMPTIVE)); }
-    public void preemptiveAuth(boolean preemptive) { accountManager.setUserData(account, KEY_AUTH_PREEMPTIVE, Boolean.toString(preemptive)); }
-
 
     // sync. settings
 
diff --git a/app/src/main/java/at/bitfire/davdroid/HttpClient.java b/app/src/main/java/at/bitfire/davdroid/HttpClient.java
index 4c4dc9f7..3758bc46 100644
--- a/app/src/main/java/at/bitfire/davdroid/HttpClient.java
+++ b/app/src/main/java/at/bitfire/davdroid/HttpClient.java
@@ -12,6 +12,7 @@ import android.accounts.Account;
 import android.content.Context;
 import android.os.Build;
 import android.support.annotation.NonNull;
+import android.support.annotation.Nullable;
 
 import java.io.IOException;
 import java.text.SimpleDateFormat;
@@ -21,9 +22,7 @@ import java.util.concurrent.TimeUnit;
 import java.util.logging.Level;
 import java.util.logging.Logger;
 
-import at.bitfire.dav4android.BasicDigestAuthenticator;
-import lombok.RequiredArgsConstructor;
-import okhttp3.Credentials;
+import at.bitfire.dav4android.BasicDigestAuthHandler;
 import okhttp3.Interceptor;
 import okhttp3.OkHttpClient;
 import okhttp3.Request;
@@ -46,13 +45,9 @@ public class HttpClient {
     public static OkHttpClient create(@NonNull Context context, @NonNull Account account, @NonNull final Logger logger) throws InvalidAccountException {
         OkHttpClient.Builder builder = defaultBuilder(logger);
 
-        // use account settings for authentication and logging
+        // use account settings for authentication
         AccountSettings settings = new AccountSettings(context, account);
-
-        if (settings.preemptiveAuth())
-            builder.addNetworkInterceptor(new PreemptiveAuthenticationInterceptor(settings.username(), settings.password()));
-        else
-            builder.authenticator(new BasicDigestAuthenticator(null, settings.username(), settings.password()));
+        builder = addAuthentication(builder, null, settings.username(), settings.password());
 
         return builder.build();
     }
@@ -69,6 +64,7 @@ public class HttpClient {
         return create(App.log);
     }
 
+
     private static OkHttpClient.Builder defaultBuilder(@NonNull final Logger logger) {
         OkHttpClient.Builder builder = client.newBuilder();
 
@@ -107,24 +103,23 @@ public class HttpClient {
         return builder;
     }
 
-    private static OkHttpClient.Builder addAuthentication(@NonNull OkHttpClient.Builder builder, @NonNull String username, @NonNull String password, boolean preemptive) {
-        if (preemptive)
-            builder.addNetworkInterceptor(new PreemptiveAuthenticationInterceptor(username, password));
-        else
-            builder.authenticator(new BasicDigestAuthenticator(null, username, password));
-        return builder;
+    private static OkHttpClient.Builder addAuthentication(@NonNull OkHttpClient.Builder builder, @Nullable String host, @NonNull String username, @NonNull String password) {
+        BasicDigestAuthHandler authHandler = new BasicDigestAuthHandler(host, username, password);
+        return builder
+                .addNetworkInterceptor(authHandler)
+                .authenticator(authHandler);
     }
 
-    public static OkHttpClient addAuthentication(@NonNull OkHttpClient client, @NonNull String username, @NonNull String password, boolean preemptive) {
+    public static OkHttpClient addAuthentication(@NonNull OkHttpClient client, @NonNull String username, @NonNull String password) {
         OkHttpClient.Builder builder = client.newBuilder();
-        addAuthentication(builder, username, password, preemptive);
+        addAuthentication(builder, null, username, password);
         return builder.build();
     }
 
     public static OkHttpClient addAuthentication(@NonNull OkHttpClient client, @NonNull String host, @NonNull String username, @NonNull String password) {
-        return client.newBuilder()
-                .authenticator(new BasicDigestAuthenticator(host, username, password))
-                .build();
+        OkHttpClient.Builder builder = client.newBuilder();
+        addAuthentication(builder, host, username, password);
+        return builder.build();
     }
 
 
@@ -140,18 +135,4 @@ public class HttpClient {
         }
     }
 
-    @RequiredArgsConstructor
-    static class PreemptiveAuthenticationInterceptor implements Interceptor {
-        final String username, password;
-
-        @Override
-        public Response intercept(Chain chain) throws IOException {
-            App.log.fine("Adding basic authorization header for user " + username);
-            Request request = chain.request().newBuilder()
-                    .header("Authorization", Credentials.basic(username, password))
-                    .build();
-            return chain.proceed(request);
-        }
-    }
-
 }
diff --git a/app/src/main/java/at/bitfire/davdroid/ui/AccountSettingsActivity.java b/app/src/main/java/at/bitfire/davdroid/ui/AccountSettingsActivity.java
index 735532bc..4a37994c 100644
--- a/app/src/main/java/at/bitfire/davdroid/ui/AccountSettingsActivity.java
+++ b/app/src/main/java/at/bitfire/davdroid/ui/AccountSettingsActivity.java
@@ -114,17 +114,6 @@ public class AccountSettingsActivity extends AppCompatActivity {
                 }
             });
 
-            final SwitchPreferenceCompat prefPreemptive = (SwitchPreferenceCompat)findPreference("preemptive");
-            prefPreemptive.setChecked(settings.preemptiveAuth());
-            prefPreemptive.setOnPreferenceChangeListener(new Preference.OnPreferenceChangeListener() {
-                @Override
-                public boolean onPreferenceChange(Preference preference, Object newValue) {
-                    settings.preemptiveAuth((Boolean)newValue);
-                    refresh();
-                    return false;
-                }
-            });
-
             // category: synchronization
             final ListPreference prefSyncContacts = (ListPreference)findPreference("sync_interval_contacts");
             final Long syncIntervalContacts = settings.getSyncInterval(ContactsContract.AUTHORITY);
diff --git a/app/src/main/java/at/bitfire/davdroid/ui/DebugInfoActivity.java b/app/src/main/java/at/bitfire/davdroid/ui/DebugInfoActivity.java
index 21926dae..93ee19b7 100644
--- a/app/src/main/java/at/bitfire/davdroid/ui/DebugInfoActivity.java
+++ b/app/src/main/java/at/bitfire/davdroid/ui/DebugInfoActivity.java
@@ -213,7 +213,6 @@ public class DebugInfoActivity extends AppCompatActivity implements LoaderManage
                                   "  Address book sync. interval: ").append(syncStatus(settings, ContactsContract.AUTHORITY)).append("\n" +
                                   "  Calendar     sync. interval: ").append(syncStatus(settings, CalendarContract.AUTHORITY)).append("\n" +
                                   "  OpenTasks    sync. interval: ").append(syncStatus(settings, "org.dmfs.tasks")).append("\n" +
-                                  "  Preemptive auth: ").append(settings.preemptiveAuth()).append("\n" +
                                   "  WiFi only: ").append(settings.getSyncWifiOnly());
                     if (settings.getSyncWifiOnlySSID() != null)
                         report.append(", SSID: ").append(settings.getSyncWifiOnlySSID());
diff --git a/app/src/main/java/at/bitfire/davdroid/ui/setup/AccountDetailsFragment.java b/app/src/main/java/at/bitfire/davdroid/ui/setup/AccountDetailsFragment.java
index a044a84f..01601990 100644
--- a/app/src/main/java/at/bitfire/davdroid/ui/setup/AccountDetailsFragment.java
+++ b/app/src/main/java/at/bitfire/davdroid/ui/setup/AccountDetailsFragment.java
@@ -107,7 +107,7 @@ public class AccountDetailsFragment extends Fragment {
         Account account = new Account(accountName, Constants.ACCOUNT_TYPE);
 
         // create Android account
-        Bundle userData = AccountSettings.initialUserData(config.userName, config.preemptive);
+        Bundle userData = AccountSettings.initialUserData(config.userName);
         App.log.log(Level.INFO, "Creating Android account with initial config", new Object[] { account, userData });
 
         AccountManager accountManager = AccountManager.get(getContext());
diff --git a/app/src/main/java/at/bitfire/davdroid/ui/setup/DavResourceFinder.java b/app/src/main/java/at/bitfire/davdroid/ui/setup/DavResourceFinder.java
index 7c9f45eb..21a297ff 100644
--- a/app/src/main/java/at/bitfire/davdroid/ui/setup/DavResourceFinder.java
+++ b/app/src/main/java/at/bitfire/davdroid/ui/setup/DavResourceFinder.java
@@ -78,7 +78,7 @@ public class DavResourceFinder {
         log.addHandler(logBuffer);
 
         httpClient = HttpClient.create(log);
-        httpClient = HttpClient.addAuthentication(httpClient, credentials.userName, credentials.password, credentials.authPreemptive);
+        httpClient = HttpClient.addAuthentication(httpClient, credentials.userName, credentials.password);
 	}
 
 
@@ -88,7 +88,7 @@ public class DavResourceFinder {
                 calDavConfig = findInitialConfiguration(Service.CALDAV);
 
         return new Configuration(
-                credentials.userName, credentials.password, credentials.authPreemptive,
+                credentials.userName, credentials.password,
                 cardDavConfig, calDavConfig,
                 logBuffer.toString()
         );
@@ -371,7 +371,6 @@ public class DavResourceFinder {
         }
 
         public final String userName, password;
-        public final boolean preemptive;
 
         public final ServiceInfo cardDAV;
         public final ServiceInfo calDAV;
diff --git a/app/src/main/java/at/bitfire/davdroid/ui/setup/LoginCredentials.java b/app/src/main/java/at/bitfire/davdroid/ui/setup/LoginCredentials.java
index 648d51a0..9fb3960a 100644
--- a/app/src/main/java/at/bitfire/davdroid/ui/setup/LoginCredentials.java
+++ b/app/src/main/java/at/bitfire/davdroid/ui/setup/LoginCredentials.java
@@ -19,7 +19,6 @@ import lombok.RequiredArgsConstructor;
 public class LoginCredentials implements Parcelable {
     public final URI uri;
     public final String userName, password;
-    public final boolean authPreemptive;
 
     @Override
     public int describeContents() {
@@ -31,7 +30,6 @@ public class LoginCredentials implements Parcelable {
         dest.writeSerializable(uri);
         dest.writeString(userName);
         dest.writeString(password);
-        dest.writeValue(authPreemptive);
     }
 
     public static final Creator CREATOR = new Creator<LoginCredentials>() {
@@ -39,8 +37,7 @@ public class LoginCredentials implements Parcelable {
         public LoginCredentials createFromParcel(Parcel source) {
             return new LoginCredentials(
                     (URI)source.readSerializable(),
-                    source.readString(), source.readString(),
-                    (boolean)source.readValue(null)
+                    source.readString(), source.readString()
             );
         }
 
diff --git a/app/src/main/java/at/bitfire/davdroid/ui/setup/LoginCredentialsFragment.java b/app/src/main/java/at/bitfire/davdroid/ui/setup/LoginCredentialsFragment.java
index 954df682..0a3b057b 100644
--- a/app/src/main/java/at/bitfire/davdroid/ui/setup/LoginCredentialsFragment.java
+++ b/app/src/main/java/at/bitfire/davdroid/ui/setup/LoginCredentialsFragment.java
@@ -43,7 +43,6 @@ public class LoginCredentialsFragment extends Fragment implements CompoundButton
     LinearLayout urlDetails;
     EditText editBaseURL, editUserName;
     EditPassword editUrlPassword;
-    CheckBox checkPreemptiveAuth;
 
 
     @Override
@@ -60,7 +59,6 @@ public class LoginCredentialsFragment extends Fragment implements CompoundButton
         editBaseURL = (EditText)v.findViewById(R.id.base_url);
         editUserName = (EditText)v.findViewById(R.id.user_name);
         editUrlPassword = (EditPassword)v.findViewById(R.id.url_password);
-        checkPreemptiveAuth = (CheckBox)v.findViewById(R.id.preemptive_auth);
 
         radioUseEmail.setOnCheckedChangeListener(this);
         radioUseURL.setOnCheckedChangeListener(this);
@@ -114,7 +112,7 @@ public class LoginCredentialsFragment extends Fragment implements CompoundButton
                 valid = false;
             }
 
-            return valid ? new LoginCredentials(uri, email, password, true) : null;
+            return valid ? new LoginCredentials(uri, email, password) : null;
 
         } else if (radioUseURL.isChecked()) {
             URI uri = null;
@@ -159,7 +157,7 @@ public class LoginCredentialsFragment extends Fragment implements CompoundButton
                 valid = false;
             }
 
-            return valid ? new LoginCredentials(uri, userName, password, checkPreemptiveAuth.isChecked()) : null;
+            return valid ? new LoginCredentials(uri, userName, password) : null;
         }
 
         return null;
diff --git a/app/src/main/res/layout/login_credentials_fragment.xml b/app/src/main/res/layout/login_credentials_fragment.xml
index bbc04c56..3ea46896 100644
--- a/app/src/main/res/layout/login_credentials_fragment.xml
+++ b/app/src/main/res/layout/login_credentials_fragment.xml
@@ -94,13 +94,6 @@
                     android:layout_height="wrap_content"
                     android:hint="@string/login_password"/>
 
-                <CheckBox
-                    android:id="@+id/preemptive_auth"
-                    android:layout_width="wrap_content"
-                    android:layout_height="wrap_content"
-                    android:text="@string/login_auth_preemptive"
-                    android:checked="true"/>
-
             </LinearLayout>
 
         </RadioGroup>
diff --git a/app/src/main/res/xml/settings_account.xml b/app/src/main/res/xml/settings_account.xml
index 3b3eff8c..9cd603c2 100644
--- a/app/src/main/res/xml/settings_account.xml
+++ b/app/src/main/res/xml/settings_account.xml
@@ -25,13 +25,6 @@
             android:summary="@string/settings_password_summary"
             android:dialogTitle="@string/settings_enter_password" />
 
-        <SwitchPreferenceCompat
-            android:key="preemptive"
-            android:persistent="false"
-            android:title="@string/settings_preemptive"
-            android:summaryOn="@string/settings_preemptive_on"
-            android:summaryOff="@string/settings_preemptive_off" />
-
     </PreferenceCategory>
 
     <PreferenceCategory android:title="@string/settings_sync">
diff --git a/dav4android b/dav4android
index bf2004e9..ff40bfd6 160000
--- a/dav4android
+++ b/dav4android
@@ -1 +1 @@
-Subproject commit bf2004e9052241345c435c2d46090ab9baf43eb8
+Subproject commit ff40bfd61f40a445b0e9414ae15b4a02fb95f64b