The links for the 3.1.0 firmware are:
Mark 4 (Aura HD, Glo)
http://download.kobobooks.com/firmwa...date-3.1.0.zip
Mark 5 (Aura)
http://download.kobobooks.com/firmwa...date-3.1.0.zip
I have only tested these downloads on an Aura HD, Glo and Aura. While the Mark4 should load on a Touch N905C or a Mini, I have not tested this. Given the lack of support for the Mini in the last firmware release and the lack of a mark3 release for 3.1.0, it's definitely something to be done knowing that it may require a factory reset.
Regards,
David