I just increased my multisite file upload limit in 'network settings', and got this warning message :-
"Document upload directory changed, but existing uploads may need to be moved to the new folder to ensure they remain accessible."
I've used 'WP Document Revisions' plugin to upload several PDF's, which I can see in folder location...wp-content/blogs.dir/2/files/2012/03 , along with several long alphanumeric .pdf filenames in ......files/2012/04 .
Problem is all my links to those files seem to be broken and I don't know where to move any of the files to correct those links (as suggested in the message). I can't access the files in the plugin either, so will I have to upload them all again?