diff --git a/UPGRADING.INTERNALS b/UPGRADING.INTERNALS
index 3b23884583dcb..b8ccdc7fb6e7e 100644
--- a/UPGRADING.INTERNALS
+++ b/UPGRADING.INTERNALS
@@ -91,6 +91,7 @@ PHP 8.4 INTERNALS UPGRADE NOTES
    - Symbol DBA_CDB_MAKE removed in ext/dba.
    - Symbol HAVE_LIBM has been removed.
    - Symbol HAVE_INET_ATON has been removed.
+   - The Zend/zend_istdiostream.h header has been removed.
 
  b. Unix build system changes
    - The configure option --with-imap-ssl has been removed.
diff --git a/Zend/zend_config.w32.h b/Zend/zend_config.w32.h
index da6b1f89580fb..ffd5f1736ee4a 100644
--- a/Zend/zend_config.w32.h
+++ b/Zend/zend_config.w32.h
@@ -38,10 +38,6 @@
 
 #include <float.h>
 
-#define HAVE_STDIOSTR_H 1
-#define HAVE_CLASS_ISTDIOSTREAM
-#define istdiostream stdiostream
-
 #if _MSC_VER < 1900
 #define snprintf _snprintf
 #endif
diff --git a/Zend/zend_istdiostream.h b/Zend/zend_istdiostream.h
deleted file mode 100644
index 74470d2ae5882..0000000000000
--- a/Zend/zend_istdiostream.h
+++ /dev/null
@@ -1,34 +0,0 @@
-/*
-   +----------------------------------------------------------------------+
-   | Zend Engine                                                          |
-   +----------------------------------------------------------------------+
-   | Copyright (c) Zend Technologies Ltd. (http://www.zend.com)           |
-   +----------------------------------------------------------------------+
-   | This source file is subject to version 2.00 of the Zend license,     |
-   | that is bundled with this package in the file LICENSE, and is        |
-   | available through the world-wide-web at the following url:           |
-   | http://www.zend.com/license/2_00.txt.                                |
-   | If you did not receive a copy of the Zend license and are unable to  |
-   | obtain it through the world-wide-web, please send a note to          |
-   | license@zend.com so we can mail you a copy immediately.              |
-   +----------------------------------------------------------------------+
-   | Authors: Andi Gutmans <andi@php.net>                                 |
-   |          Zeev Suraski <zeev@php.net>                                 |
-   +----------------------------------------------------------------------+
-*/
-
-#ifndef _ZEND_STDIOSTREAM
-#define _ZEND_STDIOSTREAM
-
-#if defined(ZTS) && !defined(HAVE_CLASS_ISTDIOSTREAM)
-class istdiostream : public istream
-{
-private:
-	stdiobuf _file;
-public:
-	istdiostream (FILE* __f) : istream(), _file(__f) { init(&_file); }
-	stdiobuf* rdbuf()/* const */ { return &_file; }
-};
-#endif
-
-#endif