[racket] Upgrading from 4.2 to 5.0 (Racket)

Apologies if this was on the download page or release notes but I
couldn't find it.

What is the best way to upgrade from 4.2 to 5.0?

Some possibilities I can imagine, multiple choice:

[a] Install 5.0. (Maybe it's an in-place upgrade, 5.0 will find/use
4.2 prefs/config and remove 4.2?)
[b] Install 5.0,then uninstall 4.2.  (Maybe so 5.0 can find/use
existing 4.2 prefs/config?)
[c] Uninstall 4.2, then install 5.0. (Maybe the uninstall of 4.2 would
somehow foobar 5.0?)

?

Thank you.