Flex 4.1 to Flex 4.5 - SDK Errors

Hi Developers,

We are looking to upgrade from Flex 4.1 to Flex 4.5. We've downloaded the trial version of 4.5 to test the build before making a purchase decision as it's primarily targetted at iPAD development.

After downloading 4.5 SDK, when we imported 4.1 Projects in 4.5, we are getting errors at the time of build. We have many projects which are developed in 4.1 and will continue to be modified/supported if we move to 4.5 but we can't afford to modify the code of those if that's what will solve the issue

I would greatly appriciate if someone knows that What exactly is the cause for this and what's the workaround?

Cheers!!!

AP