diff --git a/UPGRADING.INTERNALS b/UPGRADING.INTERNALS
index c79bd44556da..83ef90e55587 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
 ========================
@@ -100,6 +107,12 @@ PHP 8.6 INTERNALS UPGRADE NOTES
     `void **mod_data, zend_string *save_path, zend_string *session_name`
     rather than
     `void **mod_data, const char *save_path, const char *session_name`
+  . PS_FUNCS() now includes the PS_VALIDATE_SID_FUNC()
+  . PS_MOD() now requires that the PS_CREATE_SID_FUNC() and
+    PS_VALIDATE_SID_FUNC() functions are defined.
+  . PS_FUNCS_SID() and PS_MOD_SID() have been removed.
+    Either use PS_FUNCS()/PS_MOD() or PS_FUNCS_UPDATE_TIMESTAMP()/
+    PS_MOD_UPDATE_TIMESTAMP() if timestamp support exists.
 
 - ext/standard:
   . _php_error_log() now has a formal return type of zend_result.
diff --git a/configure.ac b/configure.ac
index beeed7eb2111..d89d40ff85c2 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 21baa59ffed0..ce17c0810835 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/ftp/php_ftp.c b/ext/ftp/php_ftp.c
index ffba1192f058..245d95bf1260 100644
--- a/ext/ftp/php_ftp.c
+++ b/ext/ftp/php_ftp.c
@@ -678,11 +678,8 @@ PHP_FUNCTION(ftp_pasv)
 	}
 	GET_FTPBUF(ftp, z_ftp);
 
-	if (!ftp_pasv(ftp, pasv ? 1 : 0)) {
-		RETURN_FALSE;
-	}
+	RETURN_BOOL(ftp_pasv(ftp, pasv ? 1 : 0));
 
-	RETURN_TRUE;
 }
 /* }}} */
 
diff --git a/ext/phar/func_interceptors.c b/ext/phar/func_interceptors.c
index f7e553a45ce8..5d5242e59009 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 4bd1e85666b8..4bd53c98fced 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/readline/readline.c b/ext/readline/readline.c
index 61129194db20..dad6a726f1bf 100644
--- a/ext/readline/readline.c
+++ b/ext/readline/readline.c
@@ -495,10 +495,8 @@ PHP_FUNCTION(readline_completion_function)
 
 	/* NOTE: The rl_attempted_completion_function variable (and others) are part of the readline library, not php */
 	rl_attempted_completion_function = php_readline_completion_cb;
-	if (rl_attempted_completion_function == NULL) {
-		RETURN_FALSE;
-	}
-	RETURN_TRUE;
+	
+	RETURN_BOOL(rl_attempted_completion_function != NULL);
 }
 
 /* }}} */
diff --git a/ext/session/mod_mm.c b/ext/session/mod_mm.c
index a2d9a5641e7f..d6312c5fa1f3 100644
--- a/ext/session/mod_mm.c
+++ b/ext/session/mod_mm.c
@@ -215,7 +215,7 @@ static zend_result ps_mm_key_exists(ps_mm *data, const zend_string *key)
 }
 
 const ps_module ps_mod_mm = {
-	PS_MOD_SID(mm)
+	PS_MOD(mm)
 };
 
 #define PS_MM_DATA ps_mm *data = PS_GET_MOD_DATA()
@@ -346,26 +346,7 @@ PS_READ_FUNC(mm)
 
 	mm_lock(data->mm, MM_LOCK_RD);
 
-	/* If there is an ID and strict mode, verify existence */
-	if (PS(use_strict_mode)
-		&& ps_mm_key_exists(data, key) == FAILURE) {
-		/* key points to PS(id), but cannot change here. */
-		if (key) {
-			efree(PS(id));
-			PS(id) = NULL;
-		}
-		PS(id) = PS(mod)->s_create_sid((void **)&data);
-		if (!PS(id)) {
-			return FAILURE;
-		}
-		if (PS(use_cookies)) {
-			PS(send_cookie) = true;
-		}
-		php_session_reset_id();
-		PS(session_status) = php_session_active;
-	}
-
-	sd = ps_sd_lookup(data, PS(id), false);
+	sd = ps_sd_lookup(data, key, false);
 	if (sd) {
 		*val = zend_string_init(sd->data, sd->datalen, false);
 		ret = SUCCESS;
@@ -488,4 +469,23 @@ PS_CREATE_SID_FUNC(mm)
 	return sid;
 }
 
+/*
+ * Check session ID existence for use_strict_mode support.
+ * PARAMETERS: PS_VALIDATE_SID_ARGS in php_session.h
+ * RETURN VALUE: SUCCESS or FAILURE.
+ *
+ * Return SUCCESS for valid key(already existing session).
+ * Return FAILURE for invalid key(non-existing session).
+ * *mod_data, *key are guaranteed to have non-NULL values.
+ */
+PS_VALIDATE_SID_FUNC(mm)
+{
+	PS_MM_DATA;
+
+	mm_lock(data->mm, MM_LOCK_RD);
+	zend_result ret = ps_mm_key_exists(data, key)
+	mm_unlock(data->mm);
+	return ret;
+}
+
 #endif
diff --git a/ext/session/php_session.h b/ext/session/php_session.h
index 8c857d29a5fc..836546867585 100644
--- a/ext/session/php_session.h
+++ b/ext/session/php_session.h
@@ -62,7 +62,7 @@ typedef struct ps_module_struct {
 #define PS_VALIDATE_SID_FUNC(x)	zend_result ps_validate_sid_##x(PS_VALIDATE_SID_ARGS)
 #define PS_UPDATE_TIMESTAMP_FUNC(x) 	zend_result ps_update_timestamp_##x(PS_UPDATE_TIMESTAMP_ARGS)
 
-/* Legacy save handler module definitions */
+/* Save handler module definitions without timestamp enabled */
 #define PS_FUNCS(x) \
 	PS_OPEN_FUNC(x); \
 	PS_CLOSE_FUNC(x); \
@@ -70,32 +70,15 @@ typedef struct ps_module_struct {
 	PS_WRITE_FUNC(x); \
 	PS_DESTROY_FUNC(x); \
 	PS_GC_FUNC(x);	\
-	PS_CREATE_SID_FUNC(x)
+	PS_CREATE_SID_FUNC(x) \
+	PS_VALIDATE_SID_FUNC(x);
 
 #define PS_MOD(x) \
-	#x, ps_open_##x, ps_close_##x, ps_read_##x, ps_write_##x, \
-	 ps_delete_##x, ps_gc_##x, php_session_create_id, \
-	 php_session_validate_sid, php_session_update_timestamp
-
-/* Legacy SID creation enabled save handler module definitions */
-#define PS_FUNCS_SID(x) \
-	PS_OPEN_FUNC(x); \
-	PS_CLOSE_FUNC(x); \
-	PS_READ_FUNC(x); \
-	PS_WRITE_FUNC(x); \
-	PS_DESTROY_FUNC(x); \
-	PS_GC_FUNC(x); \
-	PS_CREATE_SID_FUNC(x); \
-	PS_VALIDATE_SID_FUNC(x); \
-	PS_UPDATE_TIMESTAMP_FUNC(x);
-
-#define PS_MOD_SID(x) \
 	#x, ps_open_##x, ps_close_##x, ps_read_##x, ps_write_##x, \
 	 ps_delete_##x, ps_gc_##x, ps_create_sid_##x, \
-	 php_session_validate_sid, php_session_update_timestamp
+	 ps_validate_sid_##x, NULL
 
-/* Update timestamp enabled save handler module definitions
-   New save handlers should use this API */
+/* Save handlers with timestamp enabled, it is recommended to use this API */
 #define PS_FUNCS_UPDATE_TIMESTAMP(x) \
 	PS_OPEN_FUNC(x); \
 	PS_CLOSE_FUNC(x); \
diff --git a/ext/zip/zip_stream.c b/ext/zip/zip_stream.c
index 50f097de3c87..3a5e56d071f5 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 2f411ff8e8c9..66e0abe2c5fd 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