diff --git a/freqtrade/optimize/backtesting.py b/freqtrade/optimize/backtesting.py
old mode 100644
new mode 100755
index 5442e425b..27e14ba93
--- a/freqtrade/optimize/backtesting.py
+++ b/freqtrade/optimize/backtesting.py
@@ -9,6 +9,7 @@ from copy import deepcopy
 from datetime import datetime, timedelta, timezone
 from typing import Any, Dict, List, Optional, Tuple
 
+import pandas as pd
 from numpy import nan
 from pandas import DataFrame
 
@@ -1093,7 +1094,7 @@ class Backtesting:
                 for t, v in pairresults.open_date.items():
                     allinds = pairdf.loc[(pairdf['date'] < v)]
                     signal_inds = allinds.iloc[[-1]]
-                    signal_candles_only_df = signal_candles_only_df.append(signal_inds)
+                    signal_candles_only_df = pd.concat([signal_candles_only_df, signal_inds])
 
                 signal_candles_only[pair] = signal_candles_only_df