diff --git a/NEWS b/NEWS
index 411ff18e57..f274276516 100644
--- a/NEWS
+++ b/NEWS
@@ -224,6 +224,8 @@ Trunk (not on release branches yet)
 1.6.6 (unreleased)
 ------------------
 
+- Fix MPI_IS_THREAD_MAIN to return the correct value.  Thanks to
+  Lisandro Dalcin for pointing out the issue.
 - Update VT to 5.14.4.4:
   - Fix C++-11 issue.
   - Fix support for building RPMs on Fedora with CUDA libraries.