Can't update project from AIR 3.1 to AIR 3.4 or 3.5

Hello

I have a Flex mobile project for iOS and Android created one year ago with Flex 4.6.0 and Air 3.1.

It can't include the new required icons size for iOS.

I tried to update my Air SDK to 3.4 and 3.5, but my project does not compile any more

I followed the procedure for updating, using the ditto command on mac OSX, updating the namespace in the app.xml file... but it just does not compile

I have error messages like :

Could not resolve <s:LinearGradient> to a component implementation.

Could not resolve <s:SolidColor> to a component implementation.

Any idea?