I just upgraded and for my first charge I had the red light for a while and then both red and blue lights for a bit and then finally just the blue light. Didn't take very long to charge as it was only charged yesterday anyway.
For what it's worth after playing around a bit hiding the freebies, checking that all my books were there and that the few with font problems were fixed - maybe 30 minutes or so I have already dropped a bar and I haven't even had a chance to read anything yet.
This is my second Kobo as my first was exchanged due to the battery problems - I had to recharge 5 times in my first week
This second one was a bit better - only recharging every second or third day so I have high hopes that after the upgrade I might manage a bit longer. I'm going sailing in a few weeks and I won't have any way to charge it. I really want to get a week out it otherwise it's not going to be worth taking it with me.