YouTube
app for iOS
has been updated with new design and features for iPhone, iPad and
iPod touch. YouTube for iOS now lets you resume your partially watched videos on iPhone-iPad from where you have left
and also shows a progress bar for previously watched YouTube videos as you can easily
resume of watched videos from where you have left off. 
So this is pretty good
features while watching videos on YouTube as there might not internet connectivity or you may be busy for some moment so resuming videos on YouTube is a cool and needy feature for everyone.
how-to-Resume-partially-watched-videos-in-YouTube-on-iPhone-iPad
To see the new progress bar in action, launch YouTube on your iOS
device, tap Library at the bottom and hit History at the
top. 



Along with that YouTube’s new design makes more easier where you can easily;

• Find your watch history, uploads, purchases, and playlists in the new library
tab
• Reach tabs with less effort at the bottom of the app
• Understand tabs more easily with titles below each icon
• Switch between tabs from any screen
• See more videos with a smaller navigation bar
• Switch accounts, view notifications, and manage settings by tapping on your
avatar at the top right of the screen

New version of YouTube Requires iOS 8.0 or later and is compatible with
iPhone, iPad, and iPod touch YouTube App is available for download  from the App Store for free.