@PeterJones
Thanks for the tips.
None of the .exe files had the blocks.
I ran the update manually and how finally the Plugins Admin option has shown up.
I was wondering whether there was some change in nppPluginList.dll that might have been incompatible with my OS (Windows 7). But it seems everything is OK for now.
Microsoft didn’t remove the prompt, but made it configurable, so you can decide if you want to keep it or not.
Configuration can be found for example with right click --> properties on the recycle bin icon.