Have an MG6320 wirelessly connected to my laptop running Ubuntu 16.04 LTS and Libre Offcie 6.2.4.2. If I just print simple documents from Libre Office Writer, it correctly selects the lower tray. But when I create an 'envelope' document and print that, it insists on printing to the upper tray, which of course will not accept envelopes in the first place.
I tried asking about this on a Libre Office forum, but they insist it is a printer issue, not a LO issue.
As I recall, (it's been about 3 years now) I got the MG6320 driver for linux from canon.ca.
