News API only retrieve from 2017? many thanks!

Hi

I try to use jupyter notebook to scrape the news, I think the request commend should be correct please see below:

df = ek.get_news_headlines('R:IBM.N', date_from='2016-01-05T09:00:00', date_to='2016-04-05T18:00:00', count=100)
df.head()

df = ek.get_news_headlines('R:IBM.N', date_from='2017-01-05T09:00:00', date_to='2017-04-05T18:00:00', count=100)
df.head()

If I set the time period to 2016, I always get a blank response. If setting to 2017, I will get some news.

So I just wonder currently, we only can retrieve news from 2017? Many thanks!

All best!