I upgraded from 3.5.7 to 4.0 Beta:
-- to install 4.0, I was asked to allow 3.5.7 to be uninstalled. During that uninstall, I was asked whether I wanted to provide feedback to eEye as to why I chose to uninstall. This makes no sense during an upgrade.
-- my first download of the 4.0 installation files was corrupted, but the installation program didn't tell me that until after 3.5.7 had been uninstalled. Recommend a file consistency check be made before initiating install. I downloaded another copy, and it worked fine.
-- I note Blink continues to be tied to Internet Explorer. Once installation was complete, I could not initially update the files. This is because I had chosen to go offline during setup and at one point had set Internet Explorer to work offline (Tools/Work Offline). Once I changed IE back to online, the Blink update worked OK. I use Firefox almost exclusively, and would appreciate if Blink were not inextricably linked to IE.
-- Configuration information from 3.5.7 was saved fine, although the up-to-date antivirus files were overwritten with older versions from the installation files.