You might have to create a "why can't I use the viewer in Calibre 4.x in Windows 7" sticky.
Is there
any chance (and I suspect I know the answer) that the 3.48 version could at least be updated to include the latest Kobo firmware?
I finally bought a Kobo, thinking I'd be able to get back to using the collections I lost since I gave up on Sony and switched to a Kindle.
But - at least for now - the Libra isn't recognized by Calibre.
I'm hanging onto my Windows 7 laptop for a bit longer before I by a new computer with Windows 10. I try to have the same operating system at home that I use it work - just to keep from having to remember what can't be done "there" as compared to "here".