Are there any hooks for running plugin code after a core upgrade?
Specifically, I'm running into issues that a users wp-admin column choice in the 'Screen Options' are modified after an upgrade - I believe if they choose "auto". After doing an svn sw I lost my "publish" box from the post/pages page. This is causing some major issues in my wp-admin skin.
Check the filter update_feedback, he works after the update and you can use for all stuff after an update.
An example plugin can you find in this trunk.
You can use the _core_updated_successfully action hook to run your plugin code after the WordPress core upgrade.
The hook passes the current WordPress Version as parameter.
add_action( '_core_updated_successfully','your_function');
function your_function(){
//code to be executed after WordPress Core Update
}