def get_date_time_from_timestamp(timestamp):
    """Get the date time from a timestamp.

    The timestamp must have the following format:
    'year.month.day.hour.minutes'
    Example:
    '2017.12.20.10.31' -> '2017/12/20 10:31'
    """
    date_time_string = timestamp
    sp = timestamp.split('.')
    if len(sp) >= 5:
        date_time_string = '{0}/{1}/{2} {3}:{4}'.format(sp[0], sp[1], sp[2], sp[3], sp[4])
    return date_time_string