diff --git a/ANNOUNCE.rst b/ANNOUNCE.rst
index ced7db4e..81532085 100644
--- a/ANNOUNCE.rst
+++ b/ANNOUNCE.rst
@@ -1,13 +1,13 @@
 ===============================================================
- Announcing C-Blosc 1.21.4
+ Announcing C-Blosc 1.21.5
  A blocking, shuffling and lossless compression library for C
 ===============================================================
 
 What is new?
 ============
 
-This is a maintenance release.  Upgraded internal zstd from 1.5.2 to 1.5.5
-and Zlib to 1.2.13.
+This is a maintenance release. Here, we have provided a fix for a SSE2/AVX2
+build issue. Thanks to Thomas VINCENT and Mark Kittisopikul.
 
 For more info, please see the release notes in:
 
diff --git a/RELEASE_NOTES.rst b/RELEASE_NOTES.rst
index cc01e88a..7843f3b9 100644
--- a/RELEASE_NOTES.rst
+++ b/RELEASE_NOTES.rst
@@ -6,7 +6,8 @@
 Changes from 1.21.4 to 1.21.5
 =============================
 
-#XXX version-specific blurb XXX#
+* Fix SSE2/AVX2 build issue.  Fixes #352. Thanks to Thomas VINCENT
+  and Mark Kittisopikul.
 
 
 Changes from 1.21.3 to 1.21.4
diff --git a/blosc/blosc.h b/blosc/blosc.h
index 663b5dff..08f1b78b 100644
--- a/blosc/blosc.h
+++ b/blosc/blosc.h
@@ -21,7 +21,7 @@ extern "C" {
 #define BLOSC_VERSION_MINOR    21   /* for minor interface/format changes  */
 #define BLOSC_VERSION_RELEASE  5    /* for tweaks, bug-fixes, or development */
 
-#define BLOSC_VERSION_STRING   "1.21.5.dev"  /* string version.  Sync with above! */
+#define BLOSC_VERSION_STRING   "1.21.5"  /* string version.  Sync with above! */
 #define BLOSC_VERSION_REVISION "$Rev$"   /* revision version */
 #define BLOSC_VERSION_DATE     "$Date:: 2023-05-16 #$"    /* date version */