(You mean in kalu's updater (after a sysupgrade), right?)
I'd say something that specific, no. But maybe there could be some way to get there, e.g. trigger some actions if some (user-defined) packages were updated or something...
I don't want to make anything too complicated or anything, but since there already are post-sysupgrade actions that can be defined, I'm thinking I could just add a placeholder - e.g. $PACKAGES - that could be specified on command line, and replaced by the list of upgraded packages.
Then, you could make yourself a script that checks if some package (e.g. linux) was upgraded, and if so show a message/notification.