Today youtube discontinued support for their APIv2 so all RSS links in format https://gdata.youtube.com/feeds/base/users/USERNAME/uploads?alt=rss&v=2&orderby=published&client=ytapi-youtube-profile is now not working
The new RSS url is https://www.youtube.com/feeds/videos.xml?user=USERNAME
Examples
https://gdata.youtube.com/feeds/base/users/scishow/uploads?alt=rss&v=2&orderby=published&client=ytapi-youtube-profile
https://www.youtube.com/feeds/videos.xml?user=scishow
Is it possible to update all RSS url's with old url to the new one? I subscribed to about a hundred channels and importing them all manually ill be a hassle. I imagine I'm not the only one
You can read more about it here http://www.reddit.com/r/youtube/comments/339idg/youtube_just_dropped_its_support_for_rssatom_feeds/

Thanks