diff --git a/app/src/dummy/java/eu/faircode/email/Avatar.java b/app/src/dummy/java/eu/faircode/email/Avatar.java
index c57b707056..d47da41c0e 100644
--- a/app/src/dummy/java/eu/faircode/email/Avatar.java
+++ b/app/src/dummy/java/eu/faircode/email/Avatar.java
@@ -21,8 +21,6 @@ package eu.faircode.email;
 
 import android.content.Context;
 
-import org.apache.poi.ss.formula.eval.NotImplementedException;
-
 import java.util.concurrent.Callable;
 
 public class Avatar {
@@ -33,7 +31,7 @@ public class Avatar {
         return new Callable<ContactInfo.Favicon>() {
             @Override
             public ContactInfo.Favicon call() throws Exception {
-                throw new NotImplementedException("Gravatar");
+                throw new IllegalArgumentException("Gravatar");
             }
         };
     }
@@ -42,7 +40,7 @@ public class Avatar {
         return new Callable<ContactInfo.Favicon>() {
             @Override
             public ContactInfo.Favicon call() throws Exception {
-                throw new NotImplementedException("Libravatar");
+                throw new IllegalArgumentException("Libravatar");
             }
         };
     }
diff --git a/app/src/dummy/java/eu/faircode/email/Bimi.java b/app/src/dummy/java/eu/faircode/email/Bimi.java
index df9c8b9dd0..e658ef10b5 100644
--- a/app/src/dummy/java/eu/faircode/email/Bimi.java
+++ b/app/src/dummy/java/eu/faircode/email/Bimi.java
@@ -29,6 +29,6 @@ public class Bimi {
     static Pair<Bitmap, Boolean> get(
             Context context, String _domain, String selector, int scaleToPixels)
             throws IOException {
-        throw new NotImplementedException("BIMI");
+        throw new IllegalArgumentException("BIMI");
     }
 }
diff --git a/app/src/dummy/java/eu/faircode/email/Send.java b/app/src/dummy/java/eu/faircode/email/Send.java
index 3643fa62d5..2c41ce8962 100644
--- a/app/src/dummy/java/eu/faircode/email/Send.java
+++ b/app/src/dummy/java/eu/faircode/email/Send.java
@@ -29,7 +29,7 @@ public class Send {
     static final String DEFAULT_SERVER = "";
 
     public static String upload(InputStream is, DocumentFile dfile, int dLimit, int timeLimit, String host, IProgress intf) {
-        throw new NotImplementedException("Send");
+        throw new IllegalArgumentException("Send");
     }
 
     public interface IProgress {
diff --git a/app/src/dummy/java/eu/faircode/email/VirusTotal.java b/app/src/dummy/java/eu/faircode/email/VirusTotal.java
index 7e580b8fd5..ddbb4d66c6 100644
--- a/app/src/dummy/java/eu/faircode/email/VirusTotal.java
+++ b/app/src/dummy/java/eu/faircode/email/VirusTotal.java
@@ -32,19 +32,19 @@ public class VirusTotal {
     static final String URI_PRIVACY = "";
 
     static String getUrl(File file) {
-        throw new NotImplementedException("VirusTotal");
+        throw new IllegalArgumentException("VirusTotal");
     }
 
     static Bundle lookup(Context context, File file, String apiKey) {
-        throw new NotImplementedException("VirusTotal");
+        throw new IllegalArgumentException("VirusTotal");
     }
 
     static String upload(Context context, File file, String apiKey) {
-        throw new NotImplementedException("VirusTotal");
+        throw new IllegalArgumentException("VirusTotal");
     }
 
     static void waitForAnalysis(Context context, String id, String apiKey) {
-        throw new NotImplementedException("VirusTotal");
+        throw new IllegalArgumentException("VirusTotal");
     }
 
     public static class ScanResult implements Parcelable {