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

@@ -332,6 +332,11 @@ public interface DaoMessage {
             " ORDER BY sender, subject")
     Cursor getSuggestions(String query);
 
+    @Query("SELECT MIN(received)" +
+            " FROM message" +
+            " WHERE folder = :folder")
+    Long getMessageOldest(long folder);
+
     @Insert
     long insertMessage(EntityMessage message);