To clarify, all the videos are still available in the reverse chronological order. You can tap the dropdown at the top of the subs feed to change to “Most recent”(reverse chronological). “Highlights for you” is only an optional (mobile only) setting being tested. Hope this helps.
Thanks for clarifying. Make sure you've tapped the bell for the channel and selected "All notifications". Also, check that you've opted-in to email updates using these steps from YouTube on desktop: https://goo.gl/Smggp7