We are currently using AC 6.1.1 build 8705 and are planning to upgrade to the latest version. We have been advised that we can update to 6.1 or 7, but I don't really know the differences (or even why there are 2 'last versions'). Do you know if there is any documentation available of do you have any advise on that?
Also it is always recommended to go through standard documentation to know more on features and enhancement introduced in the different releases of the product.