Sorry about that. This is an issue with any new iOS update as manufacturers need time to update their apps in order to make them work with the new iOS version. Usually, you want to wait for the update, and/or check if all your existing apps work with the new iOS first before updating.
I checked and I found that the app Canon CameraWindow work with iOS 8, so you need a compatible Canon camera.
[Canon Compact Digital Cameras supporting features: 1, 2, 3, 4]
PowerShot G7 X, PowerShot SX60 HS, PowerShot N2, PowerShot G1 X Mark II, PowerShot SX700 HS, PowerShot SX600 HS, PowerShot N100, PowerShot ELPH 340 HS/IXUS 265 HS
[Canon Compact Digital Cameras supporting features: 1, 2, 3]
PowerShot G16, PowerShot S120, PowerShot S200, PowerShot SX510 HS, PowerShot SX280 HS, PowerShot N, PowerShot ELPH 330 HS/IXUS 255 HS, PowerShot ELPH 130 IS/IXUS 140, PowerShot ELPH 120 IS/IXUS 135, PowerShot A3500 IS/PowerShot A3550 IS, PowerShot S110, IXUS 245 HS
[Canon Compact Digital Cameras supporting features: 1, 2]
PowerShot ELPH 530 HS/IXUS 510 HS, PowerShot ELPH 320 HS/IXUS 240 HS
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