We deployed a feature that installs a custom site column named "Classification." It is a Choice column type. Now, we need to change the choices. We can update the XML in the feature easily enough, but it doesn't affect any of the lists already used the existing site column; they still see the old choices.
Is there any way to send a refresh signal or something to the lists that use our Classification site column feature to have those lists use the updated choices?
I think the only way to archive this is by iterating each list that uses the column and change the XML there as the column within a list has no reference to the original column any more.
Flo has a point, and I have previously been working with this issue and have made a blog post that might help you out somewhat. Have a look:
http://johanleino.wordpress.com/2009/08/11/propagating-updates-to-content-types/
SharePoint can do this.. Don't change your feature but modify the created site column in each site collection through the web UI. Changes made this way will propagate. (I hope you don't have 10.000 site collections ;)