In the 90s, how many updates were there, especially introducing new features?
I guess the problem is, if you introduce a new feature in a web app, it can be hidden by the customized design of users. Or it would just appear at a random place in the UI, forcing the user to re customize around that new feature.
Customization usually doesn't mean radically changing things. Its more about moving UI elements around or changing a List into a Grid etc. A combination of "new" highlight with a "Whats New" popup (extra points for short video intro) usually does the trick.
