diff --git a/src/memfile.c b/src/memfile.c
index d1bc96a..57c9d92 100644
--- a/src/memfile.c
+++ b/src/memfile.c
@@ -639,7 +639,8 @@
 # endif
 	    /* OpenNT is strictly POSIX (Benzinger) */
 	    /* Tandem/Himalaya NSK-OSS doesn't have sync() */
-# if defined(__OPENNT) || defined(__TANDEM)
+	    /* No sync() on Stratus VOS */
+# if defined(__OPENNT) || defined(__TANDEM) || defined(__VOS__)
 	    fflush(NULL);
 # else
 	    sync();
diff --git a/src/version.c b/src/version.c
index e74b125..38f3b78 100644
--- a/src/version.c
+++ b/src/version.c
@@ -742,6 +742,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    644,
+/**/
     643,
 /**/
     642,