Increased default download size to 4 MB

app/src/main/java/eu/faircode/email/ApplicationEx.java

@@ -418,6 +418,9 @@ public class ApplicationEx extends Application
         } else if (version < 1524) {
             if (BuildConfig.PLAY_STORE_RELEASE)
                 editor.remove("experiments");
+        } else if (version < 1525) {
+            if (!prefs.contains("download"))
+                editor.putInt("download", 512 * 1024);
         }
 
         if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O && !BuildConfig.DEBUG)

app/src/main/java/eu/faircode/email/MessageHelper.java

@@ -116,7 +116,7 @@ public class MessageHelper {
     private static File cacheDir = null;
 
     static final int SMALL_MESSAGE_SIZE = 192 * 1024; // bytes
-    static final int DEFAULT_DOWNLOAD_SIZE = 512 * 1024; // bytes
+    static final int DEFAULT_DOWNLOAD_SIZE = 4 * 1024 * 1024; // bytes
     static final String HEADER_CORRELATION_ID = "X-Correlation-ID";
 
     private static final int MAX_MESSAGE_SIZE = 10 * 1024 * 1024; // bytes