So I just saw this on WPCentral forums:
The list of features the OP says WP81.1 will include is:
Interactive live tiles
Lock screen applications will be built inside core system
Features in Action Center
Music controls in Action Center
More detailed notifications in Action Center
Dividing line in Action Center
Application Games to be deleted and replaced with Xbox One application dealing with avatar, messages, remote and other features.
Name to be decided YouTube application to be built completely with html 5 coding as requested by Google
Instagram application to have DIRECT MESSAGING and better video uploading capabilities and camera fixes UI for camera to be tweaked with enhanced features from Nokia Camera application
KIK Messenger to be finished in late June, overhauled design and html 5 support Skype with completely new design.
Messages in bubbles and chat heads similar to Facebook messenger?
Facebook messenger to have improved notifications, polished design and new set of fonts along with video chat, calling and improved emoji store
OneNote to have many new features as Word.
A possible merger Ability to set WordFlow's guide line to accent invisible
Give users choice to have invisible tiles on individual applications
New lock screen gestures input and other unique, disclosed password input technique options
Calculator upgrades to version 2 with more scientific features
Month view drastically changed in design in calendar application
Alarm application to feature a stopwatch, timer and splits
Cortana to head out of beta
Internet Explorer applications
Give uses the choice to delete Podcasts application
New voice memo application Backgrounds (Accent Colour 2)
Store with wallpapers from featured applications
Ability to favorite applications in store to better suggestions
Unit converting applications
Change colour of keyboard to black, white, gray, accent colour without changing background color
Keep word suggestion bar hidden until something is typed
Tiles to update as frequently as 30 seconds if feature is turned on by user or developer
Music volume controls to be centered
OneNote having abilities to use art tools
Facebook application from official company
Email/Outlook application to follow same design as computer base
Photos will have description such as name, place and time
Is it too good to be real? Do you think it might be true? Some items as interactive live tiles (I wouldnt wait to see them until W9, even if Microsoft announced "live tiles innovation' coming this year)make me distrust this info, but on the other hand others as 'Calculator upgrades to version 2 with more scientific features ', 'Email/Outlook application to follow same design as computer base ', 'Cortana to head out of beta ' seem quite reasonabland expected.