For those new to Dorico, when you update using the Steinberg Download Assistant, in the left window, you would click on My product downloads, then Dorico (in this case, Dorico 5).
On the right it should show Dorico Application installer, click Install (after completion, it will show “Install again” which you ignore.)
While it is updating, click to install the Version history (usually at the bottom of the list), then click Open to view. (I start reading it while it is finishing updating the application itself.) You will find sometimes very detailed information related to the update, new options, how to use the new features etc. It is succinct but detailed and to the point, sometimes a better summary (than in the User manual which has all kinds of other details, references, links etc. which it has to have in order to be complete as a manual).
Sometimes a reboot can help if you think there are problems after updating.