is not on the September list of Netflix releases, so season 6 will probably be in October.
The release date for the season 5 DVD & Blu-ray is Sept 26.
Longmire | APTN
says "Season 4 exclusive Canadian premiere Friday, Sep. 15!"
This is the first season that was released solely on Netflix Canada after A&E cancelled it. It looks promising for seasons 5 and 6 in the future for those people that don't subscribe to Netflix.