I hear that within the Manage Plugins screen, bloggers can see a notification that a certain plugin upgrade is available (I personally haven't had the opportunity to witness this yet). I think a 1-click upgrade link is also present. A few questions, though...
1) Is the above true?
2) Assuming I got it right, is this only possible with plugins that are hosted at the WordPress Plugin Directory/Repository? Can non- WP Repository plugins take advantage of this feature?
3) Is there any documentation that explains what happens when a user clicks that easy Upgrade button? (Just simple file replacement?)
4) If the above isn't true -- or for plugins not listed in the WP Plugin Dir/Repository -- what is the easiest way to get bloggers to upgrade plugin files? Having them "Add New -> Upload" a .zip file like their 1st install doesn't seem to work, as an error appears that the plugin is already installed.
5) How do most plugin developers instruct their users to upgrade? File replacement via FTP?
Thanks, anyone, for your clarifications!