Bump HG version to 2.4.0rc4

Update release notes

Documentation/CHANGES.md

@@ -4,6 +4,14 @@ This is a preview release of the v2.4.0 release.
 
 ## New features
 
+<span style="color:blue">Added in rc4</span>
+
+- __[HG]__
+ - Add `multi_recv_copy_threshold` init parameter
+ - Use this new parameter to fallback to memcpy to prevent starvation of multi-recv buffers
+ - Associate handle to HG proc
+ - `hg_proc_get_handle()` can be used to retrieve handle within proc functions
+
 <span style="color:blue">Added in rc3</span>
 
 - __[HG]__
@@ -82,6 +90,17 @@ This is a preview release of the v2.4.0 release.
 
 ## Bug fixes
 
+<span style="color:blue">Added in rc4</span>
+
+- __[HG]__
+ - Fix couple of type changes introduced in rc1 that could have broken ABI
+ - Fix shared-memory path that was previously disabled in conjunction with libfabric transports that use the multi-recv capability
+- __[HG util]__
+ - Fix `dlog_free` not called when parent/child have separate dlogs
+- __[HG/NA]__
+ - Fix init info changes made in previous rcs to prevent ABI breakage 
+ - HG NA init info is fixed to v4.0 for now and duplicates tclass info
+
 <span style="color:blue">Added in rc3</span>
 
 - __[HG]__

version.txt

@@ -1 +1 @@
-2.4.0rc3
+2.4.0rc4