diff --git a/doc/en/html/about/history.html b/doc/en/html/about/history.html
index c7d5b32ed..fdda40d1f 100644
--- a/doc/en/html/about/history.html
+++ b/doc/en/html/about/history.html
@@ -33,6 +33,30 @@ <h1>History</h1>
 
 <h2 id="teraterm">Tera Term</h2>
 
+<h3 id="teraterm_5.6.3">YYYY.MM.DD (Ver 5.6.3 not released yet)</h3>
+<ul class="history">
+  <!--li>Changes
+    <ul>
+      <li>
+      </li>
+    </ul>
+  </li-->
+
+  <!--li>Bug fixes
+    <ul>
+      <li>
+      </li>
+    </ul>
+  </li-->
+
+  <!--li>Misc
+    <ul>
+      <li>
+      </li>
+    </ul>
+  </li-->
+</ul>
+
 <h3 id="teraterm_5.6.2">2026.07.15 (Ver 5.6.2)</h3>
 <ul class="history">
   <li>Changes
@@ -4183,6 +4207,30 @@ <h3 id="teraterm_0.0">1994.2.24 (Ver 0.0)</h3>
 
 <h2 id="ttssh">TTSSH</h2>
 
+<h3 id="ttssh_3.6.3">YYYY.MM.DD (Ver 3.6.3 not released yet)</h3>
+<ul class="history">
+  <!--li>Changes
+    <ul>
+      <li>
+      </li>
+    </ul>
+  </li-->
+
+  <!--li>Bug fixes
+    <ul>
+      <li>
+      </li>
+    </ul>
+  </li-->
+
+  <!--li>Misc
+    <ul>
+      <li>
+      </li>
+    </ul>
+  </li-->
+</ul>
+
 <h3 id="ttssh_3.6.2">2026.07.15 (Ver 3.6.2)</h3>
 <ul class="history">
   <li>Security fixes
diff --git a/doc/ja/html/about/history.html b/doc/ja/html/about/history.html
index 120dc3d93..0c5e389d5 100644
--- a/doc/ja/html/about/history.html
+++ b/doc/ja/html/about/history.html
@@ -33,6 +33,30 @@ <h1>
 
 <h2 id="teraterm">Tera Term</h2>
 
+<h3 id="teraterm_5.6.3">YYYY.MM.DD (Ver 5.6.3 not released yet)</h3>
+<ul class="history">
+  <!--li>•ΟX
+    <ul>
+      <li>
+      </li>
+    </ul>
+  </li-->
+
+  <!--li>ƒoƒOC³
+    <ul>
+      <li>
+      </li>
+    </ul>
+  </li-->
+
+  <!--li>‚»‚Μ‘Ό
+    <ul>
+      <li>
+      </li>
+    </ul>
+  </li-->
+</ul>
+
 <h3 id="teraterm_5.6.2">2026.07.15 (Ver 5.6.2)</h3>
 <ul class="history">
   <li>•ΟX
@@ -4191,6 +4215,30 @@ <h3 id="teraterm_0.0">1994.2.24 (Ver 0.0)</h3>
 
 <h2 id="ttssh">TTSSH</h2>
 
+<h3 id="ttssh_3.6.3">YYYY.MM.DD (Ver 3.6.3 not released yet)</h3>
+<ul class="history">
+  <!--li>•ΟX
+    <ul>
+      <li>
+      </li>
+    </ul>
+  </li-->
+
+  <!--li>ƒoƒOC³
+    <ul>
+      <li>
+      </li>
+    </ul>
+  </li-->
+
+  <!--li>‚»‚Μ‘Ό
+    <ul>
+      <li>
+      </li>
+    </ul>
+  </li-->
+</ul>
+
 <h3 id="ttssh_3.6.2">2026.07.15 (Ver 3.6.2)</h3>
 <ul class="history">
   <li>ƒZƒLƒ…ƒŠƒeƒBC³
diff --git a/teraterm/common/tt-version.h b/teraterm/common/tt-version.h
index c457372f7..bc41256d6 100644
--- a/teraterm/common/tt-version.h
+++ b/teraterm/common/tt-version.h
@@ -30,8 +30,8 @@
 
 #define TT_VERSION_MAJOR             5
 #define TT_VERSION_MINOR             6
-#define TT_VERSION_PATCH             2
-//#define TT_VERSION_SUBSTR            "dev"
+#define TT_VERSION_PATCH             3
+#define TT_VERSION_SUBSTR            "dev"
 //#undef TT_VERSION_SUBSTR
 // SUBSTR が不要γͺ時は undef する
 //  使用例 "dev", "RC", "RC2"
diff --git a/ttssh2/ttxssh/ttxssh-version.h b/ttssh2/ttxssh/ttxssh-version.h
index 147676a62..4e83778cd 100644
--- a/ttssh2/ttxssh/ttxssh-version.h
+++ b/ttssh2/ttxssh/ttxssh-version.h
@@ -32,7 +32,7 @@
 
 #define TTSSH_VERSION_MAJOR             3
 #define TTSSH_VERSION_MINOR             6
-#define TTSSH_VERSION_PATCH             2
+#define TTSSH_VERSION_PATCH             3
 #define TTSSH_VERSION_STR(sep)          TT_TOSTR(TTSSH_VERSION_MAJOR) sep TT_TOSTR(TTSSH_VERSION_MINOR) sep TT_TOSTR(TTSSH_VERSION_PATCH)
 #define TTSSH_RES_VERSION_STR           TTSSH_VERSION_STR(", ") ", 0"