title: How to read pickle files generated from old versions of pandas with newer version of pandas?
body: <p>I have a pickled Dataframe that I saved with an old version of pandas (0.19.2). Trying to read it (pd.read_pickle()) with a new version of Pandas (0.20.3) throws an error: </p>
  
  <p>ModuleNotFoundError: No module named 'pandas.indexes'</p>
  
  <p>Is there any way, how I can retrieve that pickled dataframe with the new pandas version, without having to go back and save it differently in the older version?</p>
  
  <p>If not, what is the safest and easiest way to store dataframes, so that they can be easily read in the future? I read about HDFStore, which seems rather cumbersome....</p>