Dropbox 2.0.10 is now available for Mac users with a fix for icon overlays not updating on Tiger. It's certainly been a while since OS X 10.4 was last mentioned in a Dropbox changelog.
In Dropbox 2, when someone shares a link with you, the app will now show it to you straight away, and if a friend shares a folder with you, a prompt will appear in the drop-down menu where you can accept or decline the invitation.
That's for people who haven't updated in a while. For those who are on par with these changes, the new Dropbox 2.0.10 brings a couple of minor tweaks, one of which targets OS X 10.4 (Tiger users).
The new version patches icon overlays not updating on Tiger.
The newest features are only available in Mac OSX 10.6.8 (Snow Leopard) and later versions. A bunch of bug fixes are also included, which you can check out in the release notes.