Update 2.0 release announcement.

ANNOUNCE

@@ -1,76 +1,38 @@
-GNUstep Objective-C Runtime 1.x
+GNUstep Objective-C Runtime 2.0
 ===============================
 
-This the ninth official release of the GNUstep Objective-C runtime (a.k.a.
+This the second major release of the GNUstep Objective-C runtime (a.k.a.
 libobjc2).  This runtime was designed to support the features of modern
 dialects of Objective-C for use with GNUstep and other Objective-C programs.
-Highlights of this release include:
 
-- Support for 64-bit ARM (AArch64) processors, including assembly fast paths
+This release introduces a new Objective-C ABI, which is designed to be forward
-  for message sending.
+compatible with future changes and removes a large number of hacks that were
+required for compatibility with the prior ABI that included features introduced
+in the 1980s.
 
-- Improved the dispatch table representation to improve performance and cache
+The runtime will now use the new ABI's data structures internally and will
-  usage on the fast path.
+automatically upgrade on-disk structures from old ABIs when used with the old
+ABI.  As a result, memory usage will be higher when using the old ABI and users
+who are unable to recompile their code may prefer to stick with the 1.9.x
+release series.  Mixing libraries compiled with the old and new ABIs is not
+supported and will abort at run time.
 
-- The implementation of `imp_implementationWithBlock`, the function that allows
+The new ABI provides better run-time introspection metadata and smaller
-  blocks to be used as methods, no longer requires physical pages to be mapped
+binaries.  When used with the new ABI, this version of the runtime will consume
-  both writeable and executable.
+less memory than the previous release.
 
-- Numerous improvements to the interaction between runtime functions and ARC.
+You may obtain the code for this release from git and use the 2.0 branch:
-
-- Support for Thumb-2 interworking on ARM.  Note that the library must be
-  compiled for ARMv7 or ARMv6T2 for this code to be enabled.  Once it has been,
-  other Objective-C binaries linked with the library can be compiled as ARM or
-  Thumb-2 code.  This will also generate Thumb-2 message send functions,
-  improving instruction cache usage.
-
-- Significant improvements to ARC, including
-
-  * The runtime no longer acquires a global lock on every object deallocation (a
-    global lock is still used for objects that have weak references). *NOTE:*
-    This is incompatible with other code directly inspecting the reference
-    count and will break with older versions of GNUstep Base!
-
-  * Weak references use a scheme closer to C++ `std::weak_pointer` and are
-    lazily zeroed on access.  This reduces the space overheads for weak
-    references.
-
-  * Some additional helper functions are added for use in `NSObject` and other
-    root classes,  which simplifies the layering between the runtime and the
-    Foundation (or equivalent) implementation.
-
-- Improvements to how the runtime handles layout of ivars with strong alignment
-  requirements, which should fix issues relating to using vector types in
-  Objective-C objects.
-
-- The option to build a separate libobjcxx has been removed.  The runtime will
-  now depend on the C++ standard library implementation if no useable C++
-  runtime is available.  Note that C++ exception interworking does not work
-  because LLVM's libc++abi (shipped by Apple) does not provide GNU-compatible
-  hooks and so Objective-C++ exception support will be automatically disabled
-  on this platform.  Any other platforms shipping libc++abi should consider
-  either GNU libsupc++ or libcxxrt as an alternative.
-
-You may obtain the code for this release from git and use the 1.x branch:
 
 https://github.com/gnustep/libobjc2.git
 
 Alternatively, a tarball is available from:
 
-https://github.com/gnustep/libobjc2/archive/v1.x.zip
+https://github.com/gnustep/libobjc2/archive/v2.0.zip
-https://github.com/gnustep/libobjc2/archive/v1.x.tar.gz
+https://github.com/gnustep/libobjc2/archive/v2.0.tar.gz
 
 The runtime library is responsible for implementing the core features of the
 object model, as well as exposing introspection features to the user.  The
-GNUstep runtime implements Apple's Objective-C Runtime APIs, and a small number
+GNUstep runtime implements a superset of Apple's Objective-C Runtime APIs.
-of GCC APIs for legacy compatibility.
-
-This library is based on the Étoilé Objective-C Runtime, an earlier research
-prototype, and includes support for non-fragile instance variables,
-type-dependent dispatch, and object planes.  It is fully backwards compatible
-with the FSF's GCC 4.2.1 Objective-C ABI and also implements a new ABI that is
-supported by Clang and Étoilé's LanguageKit and is required for some of the
-newer features.
 
 If you come across any problems, please file them in the issue tracker: