What release notes are you looking for?
If you click back one level you get the current release notes for 2019.2.
You have gone to Home/Sketchup/Release Notes/Older Release Notes
Click the one that says Release Notes if that is what you want.
Well that’s kinda funny then. The 2019.2 notes say it was released July 18th, 2019, ten or so days ago. I’ve restarted my good old 2017 version probably close to a hundred times in that amount of time and several times today too. Wonder why today Sketchup decided to inform me that I’m behind by a couple of years?
It may be that you have 2017 set not to check for updates in preferences. The new recent release of 2019.2 has been rolled out selectively so it may have just reached your neck of the woods and has shown up because it is set to tell you even if you don’t have Check for Updates ticked in preferences.
Just a guess.
I do indeed have “Allow checking for updates” checked so you’re probably correct that it just took sometime for me to get notified. For a few minutes anyway, I was excited for some awesome bug fixes to my old work horse. Well, back to work…and thanks for letting me down gently…cheers!