RELEASE.txt changes for MPI updates

release_docs/RELEASE.txt

@@ -55,6 +55,23 @@ New Features
 
       (ADB - 2018/07/16)
 
+    - Added checks to CMake and Autotools for the following
+      MPI functions:
+
+      MPI_Mprobe - Used for the Parallel Compression feature
+      MPI_Imrecv - Used for the Parallel Compression feature
+
+      MPI_Get_elements_x - Used for the "big Parallel I/O" feature
+      MPI_Type_size_x - Used for the "big Parallel I/O" feature
+
+      (JTH - 2018/08/02, HDFFV-10512)
+
+    - Added section to the libhdf5.settings file to indicate
+      the status of the Parallel Compression and "big Parallel I/O"
+      features.
+
+      (JTH - 2018/08/02, HDFFV-10512)
+
     Library:
     --------
     -
@@ -226,6 +243,18 @@ Bug Fixes since HDF5-1.10.2 release
 
       (JTH - 2018/07/16, HDFFV-10467)
 
+    - Added checks of the defined MPI_VERSION to guard against usage of
+      MPI-3 functions in the Parallel Compression and "big Parallel I/O"
+      features when HDF5 is built with MPI-2. Previously, the configure
+      step would pass but the build itself would fail when it could not
+      locate the MPI-3 functions used.
+
+      As a result of these new checks, HDF5 can again be built with MPI-2,
+      but the Parallel Compression feature will be disabled as it relies
+      on the MPI-3 functions used.
+
+      (JTH - 2018/08/02, HDFFV-10512)
+
     - Error checks in h5stat and when decoding messages
 
       h5stat exited with seg fault/core dumped when