My current IDE installation keeps reminding me that an upgrade is available. However, when I try to download the most recent version, it tries to download 1.8.9 and tells me that it is already installed. I tried to upgrade from within the IDE, from the Arduino web site and the Microsoft store and the results are the same.
Is 1.8.10 available? Why won't it download and install?
I don't believe Arduino has released 1.8.10 on the Windows App Store yet. If you want it immediately, you'll need to use the "Windows Installer, for Windows XP and up" or "Windows ZIP file for non admin install" versions of the Arduino IDE that are available on the downloads page:
If you just want to silence the notifications, you can uncheck "Check for updates on startup" in the File > Preferences menu.