• The assistant interface has been completely revamped, making it easier to
create "New Project", "New Target", and "New File" resources. This release of
Xcode also adds new assistant templates for both Mac OS X and iPhone OS
applications.
• A new Overview toolbar item lets you see and set the project's active Target,
Configuration, Executable, Architecture, and SDK with a single control.
• It is now possible to set a global "override" SDK as the Active SDK, making it
easy to test the build of your entire project against a different platform.
• New interface shortcuts have been added to the Build Setting inspectors
making it easy to set the desired compiler, architectures, and SDKs
• You can now add Libraries and Frameworks directly into the Target window and
relate them to the project's SDK.
• The Xcode UI now allows you to designate a library or framework as weak-
linked, to support building with newer SDKs while targeting older OS versions.
• New "Edit all in scope" option within the Xcode source editor makes it easy to
update all instances of the selected symbol within the current scope of code.
• You can now have conditional build settings assigned for any combination of
architecture and SDK.
• LLVM GCC 4.2 is a new optional compiler based on the LLVM.org open source
project. LLVM GCC 4.2 provides an LLVM-based back-end optimizer using the
GCC 4.2 front-end parser. This compiler is both source and binary compatible
with GCC 4.2 and requires the Mac OS X 10.5 SDK or "Current OS" SDK.
• GCC 4.2 is a new optional compiler with stricter C and C++ language
enforcement, security enhancements, performance optimizations, and bug fixes
over GCC 4.0. Requires the Mac OS X 10.5 SDK or "Current OS" SDK

• SDK support for targeting non-Mac OS X platforms, including iPhone OS SDK.
• GCC 4.2 & LLVM GCC 4.2 optional compilers for use with Mac OS X 10.5 SDK
• Updated assistants to create new projects, targets, and source files
• Toolbar uses a single popup to choose platform, target, and debug/release
• Integrated SCM support now works with Subversion 1.5

"Xcode 3.1 is an update release of the developer tools for Mac OS X, and is the same version included with the iPhone SDK. This release provides additional GCC and LLVM compiler options, general bug fixes, and must be installed on Leopard, Mac OS X 10.5.0 and higher. Xcode 3.1 defaults to upgrading Xcode 3.0, but may optionally be installed along side existing Xcode installations. See the accompanying release notes for detailed installation instructions, known issues, and security advisories."

Xcode 2.4.1 is the latest release of Apple Computer's integrated development environment for Mac OS X. This release addresses many known issues and is a recommended upgrade for all Xcode users of versions 2.2.1 or earlier. Please choose Show Older Release Notes from the Help menu to see the release notes for previous releases of Xcode. Additionally, the complete list of Xcode and related tools release notes can be found from within Xcode by choosing Help -> Xcode Help from the menu bar, and selecting the "Release Notes" bookmark item or look in the /Developer/ADC Reference Library/releasenotes folder.

The Xcode 2.4 release provides overall stability improvement and adds support for 64-bit Intel based Mac computers. It is recommended that all Xcode users install this update.