It seems that some links to Release notes and roadmaps are broken.
Thank you for reporting this.
It seems to have been a temporary problem - I just tested all the links and they appear to work fine.
Can you please try again, and if you still see issues, try to use another browser and/or clear the browser cache.
Don’t hesitate to get back to me if you still see the 404 pages.
Problem fixed after having cleared the cache of Firefox.