I just upgraded a 6.2.6 site to DNN 7.0.5. I also upgraded NewsFeeds to 5.0.1.
When I attempt to edit newsfeeds, it throws the following error on the page.
A critical error has occurred. Index was outside the bounds of the array.
When Searching for a possible answer, I came across the link below to the DNN forums.
That page is showing the same error.