List of app that are working and not working with iOS as of now. I have tested few and I am trying to compile the list from all the sources I can find for the iMore community
Give me your updates and I will add it to the list for people who want to upgrade.
I'll take "Likes" and "Thanks" in returns
Working:
Adventure To Fate
Afterlight
AirPort Utility
Alaska Airlines
Alien Blue (pop ups not working)
Aliens
Amex
Apple Native Bug Reporter App (yes...)
Apple Trailers
Argus
Atomic WebBrowser
Bank of America
Bastion(game data only syncs with other iOS 8 devices)
BBC iPlayer
BBC News
BBC Weather
BBM
Beats Music
BillGuard
BlackBerry Messenger
Boom Beach
Box
British Airways
Cabinet (iCloud won't sync)
Candy Crush
Casts
Chase Mobile Banking
Chess with Friends
Chordian
Clash of Clans
Codea
Comic Zeal
Corkz
ctOS Mobile (watch dogs companion app)
Cubasis
Dark Sky
Delta
Documents
Drafts
Dropbox
eBay
ecobee
Ecoute
Editorial
Engadget
Epocrates
ESPN Scorecenter
Evernote
Excel for iPad
Facebook (videos don't play?)
Facebook Messenger
Fandango
Find iPhone
FIOS Mobile
Fing
Flappy Bird
Flickr
Flipboard
Flow
Frozen: FreeFall
FTL
Gmail (including notifications!)
GoComics
Good Reader
Google Docs
Google Drive
Google Maps
Google Sheets
Google Translate
Graph Paper
Guardian News
Heartstone
Hilton
HulloMail
iMore App
Instagram
IntelliCast
iStudiez Pro
Junos Pulse
kakaotalk (with glitches)
Kik
Launch Center Pro
LinkedIn
Malificient: FreeFall
Marvin
Mr Reeder
Natwest Banking App
Natwest Business Banking App
Nest
Nest (for Nest thermostat)
NetShade
NFL Mobile
NHL Game Center
Noteshelf
Office Mobile for iPhone
Omnifocus
OneDrive
Opentable
Pac-Man Monsters
Pages
Pandora
Paper (facebook app)
PayPal
PazteUp
PcCalc
Pocket Informant
Quick Office
RapGenius
RBS Banking App
RD Client
Reeder
Reeder 2.0
Remind 101
Revision 3
Runkeeper
Santander UK Banking
Scanner Pro (removes all cloud data)
Sign Now
Sky+
Skype
Snapseed
Sleep Cycle
Sonos
SpeedTest
Spotify (radio stations are missing. tap the screen and one will play but you don't see them. Have to guess in the dark)
Stackables
Starbucks
Tapatalk Pro
Techcrunch
Temple Run 2
The Score
Thechive
Thermodo
Threema
TI-Nspire CAS
Transit
Tumblr
TuneIn Radio Pro
Tweetbot 3 (Crashes on iPad)
Twitter (can't turn off notifications or it crashes at every notification)
Ultralingua
USAA
USAA Mobile
Verse a Day
Verto Studio
Vine
VLC
VMWare Fusion
VSCOcam
Waze (non-retina, looks really bad)
Wolfram|Alpha
Word for iPad
Write-on Video
Writer Pro (Same error as Cabinet though)
Xbox Smartglass
YouTube
Zedge
Not Working:
100 Balls
1Password (iPad version seems OK)
Adobe Photoshop Touch
Amazon (partially working)
Animation Desk
AnyFont
BBC News (partially working)
Calendar 5 (partially working)
CardStar
Faithlife Study Bible
Feedly
Good for Enterprise
Google Chrome
Hangouts
Hike Messenger
HSBC Business UK
HSBC UK
iBooks
Infinity Blade
Infinity Blade II
iPhoto
LastPass
LinkedIn Pulse
Musyc
Myfitnesspal (very frequent crashes)
MyVerizon
Newsify
Pebble (starts. but notifications don't show on watch)
Pocket Casts
QuizUp
Rdio
SketchBook Ink
Snapchat (partially working)
Tado
Telldus mobile
Temple Run (original)
TMZ
Tweetbot 3
UpTo (calendar app)
USA Today
Whatsapp (check notes below)