diff --git a/readme.md b/readme.md
index ddd2f91..4c92835 100644
--- a/readme.md
+++ b/readme.md
@@ -1,5 +1,5 @@
 
-Xbyak 5.63 ; JIT assembler for x86(IA32), x64(AMD64, x86-64) by C++
+Xbyak 5.631 ; JIT assembler for x86(IA32), x64(AMD64, x86-64) by C++
 =============
 
 Abstract
@@ -333,6 +333,7 @@
 
 History
 -------------
+* 2018/Mar/06 ver 5.631 fix zero division in Cpu() on some cpu
 * 2018/Feb/14 ver 5.63 fix Cpu::setCacheHierarchy() and fix EvexModifierZero for clang<3.9(thanks to mgouicem)
 * 2018/Feb/13 ver 5.62 Cpu::setCacheHierarchy() by mgouicem and rsdubtso
 * 2018/Feb/07 ver 5.61 vmov* supports mem{k}{z}(I forgot it)
diff --git a/readme.txt b/readme.txt
index f722bad..2418e30 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 5.63
+    C++用x86(IA-32), x64(AMD64, x86-64) JITアセンブラ Xbyak 5.631
 
 -----------------------------------------------------------------------------
 ◎概要
@@ -343,6 +343,7 @@
 -----------------------------------------------------------------------------
 ◎履歴
 
+2018/03/06 ver 5.631 Cpu()の中でzero divisionが出ることがあるのを修正
 2018/02/14 ver 5.63 Cpu::setCacheHierarchy()の修正とclang<3.9のためのEvexModifierZero修正(thanks to mgouicem)
 2018/02/13 ver 5.62 Cpu::setCacheHierarchy() by mgouicem and rsdubtso
 2018/02/07 ver 5.61 vmov*がmem{k}{z}形式対応(忘れてた)
diff --git a/xbyak/xbyak.h b/xbyak/xbyak.h
index f0993fe..6c83b26 100644
--- a/xbyak/xbyak.h
+++ b/xbyak/xbyak.h
@@ -105,7 +105,7 @@
 
 enum {
 	DEFAULT_MAX_CODE_SIZE = 4096,
-	VERSION = 0x5630 /* 0xABCD = A.BC(D) */
+	VERSION = 0x5631 /* 0xABCD = A.BC(D) */
 };
 
 #ifndef MIE_INTEGER_TYPE_DEFINED
diff --git a/xbyak/xbyak_mnemonic.h b/xbyak/xbyak_mnemonic.h
index d7cc0ef..f4f77df 100644
--- a/xbyak/xbyak_mnemonic.h
+++ b/xbyak/xbyak_mnemonic.h
@@ -1,4 +1,4 @@
-const char *getVersionString() const { return "5.63"; }
+const char *getVersionString() const { return "5.631"; }
 void adc(const Operand& op, uint32 imm) { opRM_I(op, imm, 0x10, 2); }
 void adc(const Operand& op1, const Operand& op2) { opRM_RM(op1, op2, 0x10); }
 void adcx(const Reg32e& reg, const Operand& op) { opGen(reg, op, 0xF6, 0x66, isREG32_REG32orMEM, NONE, 0x38); }