diff --git a/UPGRADING.INTERNALS b/UPGRADING.INTERNALS
index c4ad30b9bad5f..83ef90e555879 100644
--- a/UPGRADING.INTERNALS
+++ b/UPGRADING.INTERNALS
@@ -75,12 +75,19 @@ PHP 8.6 INTERNALS UPGRADE NOTES
 2. Build system changes
 ========================
 
+- Abstract:
+  . Minimum required PHP version found on the host system for running scripts
+    like build/gen_stub.php during development has been updated from 7.4 to 8.1.
   . build/gen_stub.php may now generate a _decl.h file in addition to
     the _arginfo.h file, if the stub declares enums and is annotated with
     @generate-c-enums. For each enum the file will contain a C enum. Enum
     values can be compared to the result of
     zend_enum_fetch_case_id(zend_object*).
 
+- Unix build system changes:
+  . Symbol HAVE_ST_BLOCKS has been removed from php_config.h (use
+    HAVE_STRUCT_STAT_ST_BLOCKS).
+
 ========================
 3. Module changes
 ========================
diff --git a/configure.ac b/configure.ac
index beeed7eb21115..d89d40ff85c21 100644
--- a/configure.ac
+++ b/configure.ac
@@ -160,8 +160,8 @@ PHP_RUNPATH_SWITCH
 dnl Checks for some support/generator progs.
 PHP_PROG_BISON([3.0.0])
 PHP_PROG_RE2C([1.0.3], [--no-generation-date])
-dnl Find installed PHP. Minimum supported version for gen_stub.php is PHP 7.4.
-PHP_PROG_PHP([7.4])
+dnl Find installed PHP. Minimum supported version for gen_stub.php is PHP 8.1.
+PHP_PROG_PHP([8.1])
 
 PHP_ARG_ENABLE([re2c-cgoto],
   [whether to enable computed goto extension with re2c],
@@ -504,11 +504,11 @@ AS_VAR_IF([php_cv_have_alignof], [yes],
 
 dnl Check for structure members.
 AC_CHECK_MEMBERS([struct tm.tm_gmtoff],,,[#include <time.h>])
-AC_CHECK_MEMBERS([struct stat.st_blksize, struct stat.st_rdev])
-dnl AC_STRUCT_ST_BLOCKS will screw QNX because fileblocks.o does not exist.
-if test "$(uname -s 2>/dev/null)" != "QNX"; then
-  AC_STRUCT_ST_BLOCKS
-fi
+AC_CHECK_MEMBERS(m4_normalize([
+  struct stat.st_blksize,
+  struct stat.st_blocks,
+  struct stat.st_rdev
+]))
 
 dnl Checks for types.
 AC_TYPE_UID_T
diff --git a/ext/dom/xpath.c b/ext/dom/xpath.c
index 21baa59ffed0b..ce17c0810835a 100644
--- a/ext/dom/xpath.c
+++ b/ext/dom/xpath.c
@@ -227,10 +227,7 @@ PHP_METHOD(DOMXPath, registerNamespace)
 		RETURN_THROWS();
 	}
 
-	if (xmlXPathRegisterNs(ctxp, prefix, ns_uri) != 0) {
-		RETURN_FALSE;
-	}
-	RETURN_TRUE;
+	RETURN_BOOL(xmlXPathRegisterNs(ctxp, prefix, ns_uri) == 0);
 }
 /* }}} */
 
diff --git a/ext/phar/func_interceptors.c b/ext/phar/func_interceptors.c
index f7e553a45ce80..5d5242e590092 100644
--- a/ext/phar/func_interceptors.c
+++ b/ext/phar/func_interceptors.c
@@ -631,8 +631,10 @@ static void phar_file_stat(const char *filename, size_t filename_length, int typ
 			if (data) {
 				sb.st_ino = data->inode;
 			}
-#ifndef PHP_WIN32
+#ifdef HAVE_STRUCT_STAT_ST_BLKSIZE
 			sb.st_blksize = -1;
+#endif
+#ifdef HAVE_STRUCT_STAT_ST_BLOCKS
 			sb.st_blocks = -1;
 #endif
 			phar_fancy_stat(&sb, type, return_value);
diff --git a/ext/phar/stream.c b/ext/phar/stream.c
index 4bd1e85666b85..4bd53c98fced6 100644
--- a/ext/phar/stream.c
+++ b/ext/phar/stream.c
@@ -526,8 +526,10 @@ void phar_dostat(phar_archive_data *phar, phar_entry_info *data, php_stream_stat
 	if (!is_temp_dir) {
 		ssb->sb.st_ino = data->inode;
 	}
-#ifndef PHP_WIN32
+#ifdef HAVE_STRUCT_STAT_ST_BLKSIZE
 	ssb->sb.st_blksize = -1;
+#endif
+#ifdef HAVE_STRUCT_STAT_ST_BLOCKS
 	ssb->sb.st_blocks = -1;
 #endif
 }
diff --git a/ext/zip/zip_stream.c b/ext/zip/zip_stream.c
index 50f097de3c876..3a5e56d071f50 100644
--- a/ext/zip/zip_stream.c
+++ b/ext/zip/zip_stream.c
@@ -177,8 +177,10 @@ static int php_zip_ops_stat(php_stream *stream, php_stream_statbuf *ssb) /* {{{
 		ssb->sb.st_ctime = sb.mtime;
 		ssb->sb.st_nlink = 1;
 		ssb->sb.st_rdev = -1;
-#ifndef PHP_WIN32
+#ifdef HAVE_STRUCT_STAT_ST_BLKSIZE
 		ssb->sb.st_blksize = -1;
+#endif
+#ifdef HAVE_STRUCT_STAT_ST_BLOCKS
 		ssb->sb.st_blocks = -1;
 #endif
 		ssb->sb.st_ino = -1;
diff --git a/main/streams/memory.c b/main/streams/memory.c
index 2f411ff8e8c9c..66e0abe2c5fd9 100644
--- a/main/streams/memory.c
+++ b/main/streams/memory.c
@@ -213,8 +213,10 @@ static int php_stream_memory_stat(php_stream *stream, php_stream_statbuf *ssb) /
 	/* generate unique inode number for alias/filename, so no phars will conflict */
 	ssb->sb.st_ino = 0;
 
-#ifndef PHP_WIN32
+#ifdef HAVE_STRUCT_STAT_ST_BLKSIZE
 	ssb->sb.st_blksize = -1;
+#endif
+#ifdef HAVE_STRUCT_STAT_ST_BLOCKS
 	ssb->sb.st_blocks = -1;
 #endif