diff --git a/include/mimalloc.h b/include/mimalloc.h
index 5b3d13ed..e09f7d36 100644
--- a/include/mimalloc.h
+++ b/include/mimalloc.h
@@ -8,7 +8,7 @@ terms of the MIT license. A copy of the license can be found in the file
 #ifndef MIMALLOC_H
 #define MIMALLOC_H
 
-#define MI_MALLOC_VERSION 166   // major + 2 digits minor
+#define MI_MALLOC_VERSION 165   // major + 2 digits minor
 
 // ------------------------------------------------------
 // Compiler specific attributes
diff --git a/readme.md b/readme.md
index daf57f39..d8c94119 100644
--- a/readme.md
+++ b/readme.md
@@ -11,7 +11,7 @@ mimalloc (pronounced "me-malloc")
 is a general purpose allocator with excellent [performance](#performance) characteristics.
 Initially developed by Daan Leijen for the run-time systems of the
 [Koka](https://github.com/koka-lang/koka) and [Lean](https://github.com/leanprover/lean) languages.
-Latest release:`v1.6.4` (2020-08-06).
+Latest release:`v1.6.5` (2020-09-24).
 
 It is a drop-in replacement for `malloc` and can be used in other programs
 without code changes, for example, on dynamically linked ELF-based systems (Linux, BSD, etc.) you can use it as: