Skip synchronizing erroneously return old messages

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

@@ -1213,6 +1213,19 @@ class Core {
 
                 for (int j = isub.length - 1; j >= 0 && state.running() && state.recoverable(); j--)
                     try {
+                        // Some providers, like Zoho, erroneously return old messages
+                        if (full.contains(isub[j])) {
+                            Date received = isub[j].getReceivedDate();
+                            boolean unseen = (sync_unseen && !isub[j].isSet(Flags.Flag.SEEN));
+                            boolean flagged = (sync_flagged && isub[j].isSet(Flags.Flag.FLAGGED));
+                            if (received != null && received.getTime() < sync_time && !unseen && !flagged) {
+                                long uid = ifolder.getUID(isub[j]);
+                                Log.i(folder.name + " Skipping old uid=" + uid + " date=" + received);
+                                ids[from + j] = null;
+                                continue;
+                            }
+                        }
+
                         EntityMessage message = synchronizeMessage(
                                 context,
                                 account, folder,