Correct the max receive message constant

The max receive size constant (a user programme only
constant) still reflected the original limit of 4k.
While internally this was not used and/or enforced, the
incorrect setting could cause some wrapper implementations
to incorrectly limit the max receive size.

This change sets this constant to the acknowledged max
receive size for all transports (64K).

Issue-ID: RIC-301

Signed-off-by: E. Scott Daniels <daniels@research.att.com>
Change-Id: I214b9d9dd67a00232e57bab8327dcb76f891b517
diff --git a/CHANGES_CORE.txt b/CHANGES_CORE.txt
index 227f92b..a118752 100644
--- a/CHANGES_CORE.txt
+++ b/CHANGES_CORE.txt
@@ -5,6 +5,9 @@
 # API and build change  and fix summaries. Doc correctsions
 # and/or changes are not mentioned here; see the commit messages.
 
+2020 March 30; version 3.6.3
+	Correct the max receive message size constant in rmr.h (RIC-301)
+
 2020 March 23; version 3.6.2
 	Fix message initialisation bug when pulling a message from 
 	the pool (RIC-295)