Postgresql – How to install UTF8 locale on PostgreSQL

PostgreSQL really doesn't put much effort into supporting moves from newer major versions back to older ones. One big reason for that is that newer versions usually support features which you just can't install on older versions; although any given database might not be using any of the new features, the project philosophy is that they would rather not support it than to support it in a buggy or incomplete fashion.

Your best bet might be to generate a "plain" format dump rather than a "custom" format dump. This is just a text file of SQL commands. If you aren't using any new features, it might just apply cleanly. If not, you can look into the errors and decide what to do for a back-port.

I suspect your database content may be in iso8859 or cp1252. If it were ascii, you would not run into problems importing it. You may be able to determine the coding by opening your dump with python. The following python3 tries encodings until it succeeds. It can be used to determine the file encoding.

for enc in ('cp1252', 'utf8'):
    print('Encoding', enc)
    try:
        file = open(fileName, 'r', encoding=enc)
        return file.read()
    except Exception as e:
        print(e)
        return None

Python also can also be used to access the database and audit the data. It could also be used to transcode the data to UTF-8 while copying it if necessary.