Where are the latest seasons on history

I don't watch much TV.  I watch news, weather, sports, but no TV shows except for "The Curse of Oak Island" and "Ancient Aliens" both on History.  I work early hours so when these shows are on I tend to fall asleep at some point.  Its never been an issue because I use on demand to watch what I missed.  This year though, the current seasons are not on demand.  Its been weeks since each show began and nothing on demand.  What gives?