Here's the new portable installer:
http://calibre-ebook.com/downloads/b...ler-0.8.69.exe
Just run the exe and when it asks for a location, point it to your existing calibre portable folder, it will do the upgrade automatically.
Since I was in the area, I also added support for multiple libraries inside the Calibre Portable folder. You can now create new libraries inside the Calibre Portable folder and switch between them with quick switch even if the location of the Calibre Portable folder changes.
I'd appreciate it if some of you could test this a bit before I release it on Friday.