Twice I have been uploading a new plugin (never before used on the site), selected "no" for not updating an existing plugin, the plugin seems to install just fine, but I get this pink error message at the top of the page:
You must select "Yes" from the "Upgrade existing plugin?" dropdown option in order to upgrade an existing plugin. Try again.
Maybe it's not a big deal, since everything is moving toward automatic updates, but I thought you would want to know.