diff --git a/CMakeLists.txt b/CMakeLists.txt
index 5b06512..d38ec83 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,6 +1,6 @@
 cmake_minimum_required(VERSION 3.5)
 
-project(xbyak LANGUAGES CXX VERSION 7.20.1)
+project(xbyak LANGUAGES CXX VERSION 7.21)
 
 file(GLOB headers xbyak/*.h)
 
diff --git a/doc/changelog.md b/doc/changelog.md
index 47117d8..4406559 100644
--- a/doc/changelog.md
+++ b/doc/changelog.md
@@ -1,5 +1,6 @@
 # History
 
+* 2024/Oct/31 ver 7.21 Enhance XMM register validation in SSE instructions
 * 2024/Oct/17 ver 7.20.1 Updated to comply with AVX10.2 specification rev 2.0
 * 2024/Oct/15 ver 7.20 Fixed the specification of setDefaultEncoding, setDefaultEncodingAVX10.
 * 2024/Oct/15 ver 7.11 Added full support for AVX10.2
diff --git a/meson.build b/meson.build
index 5bb3b78..b7b465e 100644
--- a/meson.build
+++ b/meson.build
@@ -5,7 +5,7 @@
 project(
 	'xbyak',
 	'cpp',
-	version: '7.20.1',
+	version: '7.21',
 	license: 'BSD-3-Clause',
 	default_options: 'b_ndebug=if-release'
 )
diff --git a/readme.md b/readme.md
index a5dabdd..63a0c00 100644
--- a/readme.md
+++ b/readme.md
@@ -1,5 +1,5 @@
 
-# Xbyak 7.20.1 [![Badge Build]][Build Status]
+# Xbyak 7.21 [![Badge Build]][Build Status]
 
 *A JIT assembler for x86/x64 architectures supporting advanced instruction sets up to AVX10.2*
 
diff --git a/readme.txt b/readme.txt
index 82083cd..d9fef26 100644
--- a/readme.txt
+++ b/readme.txt
@@ -1,5 +1,5 @@
 
-    C++用x86(IA-32), x64(AMD64, x86-64) JITアセンブラ Xbyak 7.20.1
+    C++用x86(IA-32), x64(AMD64, x86-64) JITアセンブラ Xbyak 7.21
 
 -----------------------------------------------------------------------------
 ◎概要
@@ -404,6 +404,7 @@ sample/{echo,hello}.bfは http://www.kmonos.net/alang/etc/brainfuck.php から
 -----------------------------------------------------------------------------
 ◎履歴
 
+2024/10/31 ver 7.21 SSE命令のXMMレジスタのチェックを厳密化
 2024/10/17 ver 7.20.1 AVX10.2 rev 2.0仕様書の変更に追従
 2024/10/15 ver 7.20 setDefaultEncoding/setDefaultEncodingAVX10の仕様確定
 2024/10/15 ver 7.11 AVX10.2完全サポート
diff --git a/xbyak/xbyak.h b/xbyak/xbyak.h
index 2be63a1..28af005 100644
--- a/xbyak/xbyak.h
+++ b/xbyak/xbyak.h
@@ -155,7 +155,7 @@ namespace Xbyak {
 
 enum {
 	DEFAULT_MAX_CODE_SIZE = 4096,
-	VERSION = 0x7201 /* 0xABCD = A.BC(.D) */
+	VERSION = 0x7210 /* 0xABCD = A.BC(.D) */
 };
 
 #ifndef MIE_INTEGER_TYPE_DEFINED
diff --git a/xbyak/xbyak_mnemonic.h b/xbyak/xbyak_mnemonic.h
index 6015c50..64930ab 100644
--- a/xbyak/xbyak_mnemonic.h
+++ b/xbyak/xbyak_mnemonic.h
@@ -1,4 +1,4 @@
-const char *getVersionString() const { return "7.20.1"; }
+const char *getVersionString() const { return "7.21"; }
 void aadd(const Address& addr, const Reg32e &reg) { opMR(addr, reg, T_0F38, 0x0FC, T_APX); }
 void aand(const Address& addr, const Reg32e &reg) { opMR(addr, reg, T_0F38|T_66, 0x0FC, T_APX|T_66); }
 void adc(const Operand& op, uint32_t imm) { opOI(op, imm, 0x10, 2); }