The offline mode in BlinkFeed lets you view articles (text, images or both) when you are not connected to the internet. To enable offline mode in BlinkFeed on HTC One M8, do as follows:
1. Go to Home Screen and swipe right to get to the BlinkFeed
2. Swipe right again to open the side bar
3. Tap the 3dot icon and go to Settings.
4. Open Offline new reading
5. Now you have 3 options to choose: Off, Text Only, and Full artilce
** Note that, since for offline reading more data are stored, then it may cause additional data charges