Yahoo have changed the url format for downloading stock data, which doesn't work using fopen anymore
For example:
fopen('https://query1.finance.yahoo.com/v7/finance/download/AMZN?period1=1483920000&period2=1484006400&interval=1d&events=history&crumb=SqQAebjmGVM','rb');
url downloads an excel file in a browser, but returns false from PHP script?