View Paweł Sroka's plugins
Provides administration panel widget showing current version of Elgg and checking if installation is up to date. Widget is added automatically on plugin activation.
It's plugin version of the pull request to core (https://github.com/Elgg/Elgg/pull/480), so if it makes it's way, this plugin will become obsolete.
It's also my first community plugin ;-)
Ported version of https://github.com/Srokap/Elgg/commit/3e4a16b73803759d3eb4f92fac79741f49d3312f
Information on newest version is taken from github tag (or elgg.org page if for some reason, first option is not availible). If you were able to use download link on the widget, the package was already uploaded, otherwise you'd get 404 error. Main page is updated with some delay but tags should be definitive.
Can you compare previously downloaded package with the one currently available at download page ?