What's new in Gerrit 2.8: Update info about the new change screen

Mention that in 2.8 the old screen is default, in 2.9 the new
screen is default, and that in later versions the old screen
will be removed.

Change-Id: I9a8d662e9852b5505a4991bd8e8242d28ed8d48c
diff --git a/presentations/gerrit-new-features-2.8/gerrit-new-features-2.8.txt b/presentations/gerrit-new-features-2.8/gerrit-new-features-2.8.txt
index e038e64..5181da9 100644
--- a/presentations/gerrit-new-features-2.8/gerrit-new-features-2.8.txt
+++ b/presentations/gerrit-new-features-2.8/gerrit-new-features-2.8.txt
@@ -109,6 +109,10 @@
 A preference setting allows the user to decide if the new or the old
 change screen should be used.
 
+* In 2.8 the old screen is default.
+* In 2.9 the new screen is default.
+* In later versions (possibly from 2.10) the old screen will be removed.
+
 image:../../img/change-screen-preference.png[]
 
 *WARNING:* The new change screen in 2.8 is still beta.