OK, now I understand, 4.5 is in Beta! I thought this was just standard operating procedure!
About the update window that appears from time to time, usually at boot up on my friends computer: the reason my friend is getting an "update notification" is that in Avast 4 home, on the settings menu, there is an item called "Update". In the update menu item, there are radio buttons for "Virus Database" and "Program" with "Automatic"" Ask", and "Manual" choices. Apparently she has the "Ask" button checked.
The original reason for my question was to find out if she simply clicked on this window when it appears if it would automatically download and install the update, or if Avast 4 home needed to be un-installed to be upgraded to a newer version.
I was also asking for myself, as I don't have "Ask" checked in the update section of the settings menu, but "Manual" instead, so I'm not getting this update prompt, but also wanted to find out if I needed to uninstall to upgrade.
Sorry for the confusion and thanks for your patience and help. I can easily overwrite the file, I just wanted to know if this was SOP for updating the program. And of course I can wait, no rush at all. Live and learn. Thanks again.