I only have and Ipad now, used to have an Iphone. But yes you can sync between the two. You just upload to the apps cloud, and youd be able to down load it on a different devise,
Sucks the Andriod app doesn't work the same way for some stupid reason, I emailed them about it they said to keep an eye out it will be like the ios app soon. So I use my iPad to scan comics. Ive been slacking on it a lot lately though,, a lot more convenient to use a smaller devise to scan em.
I don't know about the updates or not,, I would just go to the app store on line and you should be able to see in the details.
But if you are really wanting an app to scan and keep an inventory of your books this is a really good easy app for it,, shows all the cover art and information.