diff --git a/README.md b/README.md
index 96d355cd0..0ee0a657a 100644
--- a/README.md
+++ b/README.md
@@ -91,7 +91,7 @@ Procedures for each standard are provided by the following R7RS-style libraries:
 cmake -B build -DCMAKE_BUILD_TYPE=Release
 cd build
 make package
-sudo apt install build/meevax_0.5.159_amd64.deb
+sudo apt install build/meevax_0.5.160_amd64.deb
 ```
 
 or
@@ -123,9 +123,9 @@ sudo rm -rf /usr/local/share/meevax
 
 | Target Name | Description
 |-------------|-------------
-| `all`       | Build shared-library `libmeevax.0.5.159.so` and executable `meevax`
+| `all`       | Build shared-library `libmeevax.0.5.160.so` and executable `meevax`
 | `test`      | Test executable `meevax`
-| `package`   | Generate debian package `meevax_0.5.159_amd64.deb`
+| `package`   | Generate debian package `meevax_0.5.160_amd64.deb`
 | `install`   | Copy files into `/usr/local` directly
 
 ## Usage
diff --git a/VERSION b/VERSION
index 7948d08ba..e5003ef3d 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-0.5.159
+0.5.160
diff --git a/include/meevax/memory/integer_set.hpp b/include/meevax/memory/integer_set.hpp
index a9c47d222..a9f2a2e56 100644
--- a/include/meevax/memory/integer_set.hpp
+++ b/include/meevax/memory/integer_set.hpp
@@ -48,8 +48,18 @@ inline namespace memory
 
     std::size_t max = 0;
 
-    struct const_iterator : public std::iterator<std::bidirectional_iterator_tag, T>
+    struct const_iterator
     {
+      using value_type = T;
+
+      using difference_type   = std::ptrdiff_t;
+
+      using pointer = T *;
+
+      using reference = T &;
+
+      using iterator_category = std::bidirectional_iterator_tag;
+
       subset const* const* data = nullptr;
 
       std::size_t max = 0;
@@ -273,8 +283,18 @@ inline namespace memory
 
     std::uint64_t data[N / 64] {};
 
-    struct const_iterator : public std::iterator<std::bidirectional_iterator_tag, T>
+    struct const_iterator
     {
+      using value_type = T;
+
+      using difference_type   = std::ptrdiff_t;
+
+      using pointer = T *;
+
+      using reference = T &;
+
+      using iterator_category = std::bidirectional_iterator_tag;
+
       std::uint64_t const* data = nullptr;
 
       std::size_t index = std::numeric_limits<std::size_t>::max();