diff --git a/Zend/tests/bug77494.phpt b/Zend/tests/bug77494.phpt
deleted file mode 100644
index 7f808c2c0f52a..0000000000000
--- a/Zend/tests/bug77494.phpt
+++ /dev/null
@@ -1,23 +0,0 @@
---TEST--
-Bug #77494 (Disabling class causes segfault on member access)
---EXTENSIONS--
-curl
---INI--
-disable_classes=CURLFile,ErrorException
---FILE--
-<?php
-$a = new CURLFile();
-var_dump($a->name);
-$b = new ErrorException();
-var_dump($b->message);
-?>
---EXPECTF--
-Warning: CURLFile() has been disabled for security reasons in %sbug77494.php on line 2
-
-Warning: Undefined property: CURLFile::$name in %s on line %d
-NULL
-
-Warning: ErrorException() has been disabled for security reasons in %s on line %d
-
-Warning: Undefined property: ErrorException::$message in %s on line %d
-NULL
diff --git a/Zend/tests/disable_classes_warning.phpt b/Zend/tests/disable_classes_warning.phpt
new file mode 100644
index 0000000000000..c3692bf52972f
--- /dev/null
+++ b/Zend/tests/disable_classes_warning.phpt
@@ -0,0 +1,27 @@
+--TEST--
+Check that warning is emitted when disabling classes
+--INI--
+disable_classes=Exception
+--FILE--
+<?php
+$o = new Exception();
+var_dump($o);
+?>
+--EXPECTF--
+object(Exception)#1 (7) {
+  ["message":protected]=>
+  string(0) ""
+  ["string":"Exception":private]=>
+  string(0) ""
+  ["code":protected]=>
+  int(0)
+  ["file":protected]=>
+  string(%d) "%s"
+  ["line":protected]=>
+  int(2)
+  ["trace":"Exception":private]=>
+  array(0) {
+  }
+  ["previous":"Exception":private]=>
+  NULL
+}
diff --git a/Zend/tests/errmsg_021.phpt b/Zend/tests/errmsg_021.phpt
deleted file mode 100644
index 7514e68359044..0000000000000
--- a/Zend/tests/errmsg_021.phpt
+++ /dev/null
@@ -1,17 +0,0 @@
---TEST--
-errmsg: disabled class
---INI--
-disable_classes=stdclass
---FILE--
-<?php
-
-class test extends stdclass {
-}
-
-$t = new test;
-
-echo "Done\n";
-?>
---EXPECTF--
-Warning: test() has been disabled for security reasons in %s on line %d
-Done
diff --git a/Zend/zend_API.c b/Zend/zend_API.c
index ae7a06f011761..c7d5cde2443e4 100644
--- a/Zend/zend_API.c
+++ b/Zend/zend_API.c
@@ -3579,77 +3579,6 @@ ZEND_API void zend_disable_functions(const char *function_list) /* {{{ */
 }
 /* }}} */
 
-#ifdef ZEND_WIN32
-#pragma optimize("", off)
-#endif
-static ZEND_COLD zend_object *display_disabled_class(zend_class_entry *class_type) /* {{{ */
-{
-	zend_object *intern;
-
-	intern = zend_objects_new(class_type);
-
-	/* Initialize default properties */
-	if (EXPECTED(class_type->default_properties_count != 0)) {
-		zval *p = intern->properties_table;
-		zval *end = p + class_type->default_properties_count;
-		do {
-			ZVAL_UNDEF(p);
-			p++;
-		} while (p != end);
-	}
-
-	zend_error(E_WARNING, "%s() has been disabled for security reasons", ZSTR_VAL(class_type->name));
-	return intern;
-}
-#ifdef ZEND_WIN32
-#pragma optimize("", on)
-#endif
-/* }}} */
-
-static const zend_function_entry disabled_class_new[] = {
-	ZEND_FE_END
-};
-
-ZEND_API zend_result zend_disable_class(const char *class_name, size_t class_name_length) /* {{{ */
-{
-	zend_class_entry *disabled_class;
-	zend_string *key;
-	zend_function *fn;
-	zend_property_info *prop;
-
-	key = zend_string_alloc(class_name_length, 0);
-	zend_str_tolower_copy(ZSTR_VAL(key), class_name, class_name_length);
-	disabled_class = zend_hash_find_ptr(CG(class_table), key);
-	zend_string_release_ex(key, 0);
-	if (!disabled_class) {
-		return FAILURE;
-	}
-
-	/* Will be reset by INIT_CLASS_ENTRY. */
-	free(disabled_class->interfaces);
-
-	INIT_CLASS_ENTRY_INIT_METHODS((*disabled_class), disabled_class_new);
-	disabled_class->create_object = display_disabled_class;
-
-	ZEND_HASH_MAP_FOREACH_PTR(&disabled_class->function_table, fn) {
-		if ((fn->common.fn_flags & (ZEND_ACC_HAS_RETURN_TYPE|ZEND_ACC_HAS_TYPE_HINTS)) &&
-			fn->common.scope == disabled_class) {
-			zend_free_internal_arg_info(&fn->internal_function);
-		}
-	} ZEND_HASH_FOREACH_END();
-	zend_hash_clean(&disabled_class->function_table);
-	ZEND_HASH_MAP_FOREACH_PTR(&disabled_class->properties_info, prop) {
-		if (prop->ce == disabled_class) {
-			zend_string_release(prop->name);
-			zend_type_release(prop->type, /* persistent */ 1);
-			free(prop);
-		}
-	} ZEND_HASH_FOREACH_END();
-	zend_hash_clean(&disabled_class->properties_info);
-	return SUCCESS;
-}
-/* }}} */
-
 static zend_always_inline zend_class_entry *get_scope(zend_execute_data *frame)
 {
 	return frame && frame->func ? frame->func->common.scope : NULL;
diff --git a/Zend/zend_API.h b/Zend/zend_API.h
index 90556fcde4245..697218bc3d805 100644
--- a/Zend/zend_API.h
+++ b/Zend/zend_API.h
@@ -402,7 +402,6 @@ static zend_always_inline zend_result zend_register_class_alias(const char *name
 	zend_register_class_alias_ex(ZEND_NS_NAME(ns, name), sizeof(ZEND_NS_NAME(ns, name))-1, ce, 1)
 
 ZEND_API void zend_disable_functions(const char *function_list);
-ZEND_API zend_result zend_disable_class(const char *class_name, size_t class_name_length);
 
 ZEND_API ZEND_COLD void zend_wrong_param_count(void);
 ZEND_API ZEND_COLD void zend_wrong_property_read(zval *object, zval *property);
diff --git a/main/main.c b/main/main.c
index eae9977303333..111c28bddbb87 100644
--- a/main/main.c
+++ b/main/main.c
@@ -319,41 +319,6 @@ static PHP_INI_MH(OnSetLogFilter)
 }
 /* }}} */
 
-/* {{{ php_disable_classes */
-static void php_disable_classes(void)
-{
-	char *s = NULL, *e;
-
-	if (!*(INI_STR("disable_classes"))) {
-		return;
-	}
-
-	e = PG(disable_classes) = strdup(INI_STR("disable_classes"));
-
-	while (*e) {
-		switch (*e) {
-			case ' ':
-			case ',':
-				if (s) {
-					*e = '\0';
-					zend_disable_class(s, e-s);
-					s = NULL;
-				}
-				break;
-			default:
-				if (!s) {
-					s = e;
-				}
-				break;
-		}
-		e++;
-	}
-	if (s) {
-		zend_disable_class(s, e-s);
-	}
-}
-/* }}} */
-
 /* {{{ php_binary_init */
 static void php_binary_init(void)
 {
@@ -660,6 +625,17 @@ static PHP_INI_MH(OnChangeMailForceExtra)
 }
 /* }}} */
 
+/* Emit warning when using this INI setting as it is removed */
+static PHP_INI_MH(OnChangeDisableClasses)
+{
+	if (stage != PHP_INI_SYSTEM) {
+			return FAILURE;
+	}
+	php_error_docref("disable_classes", E_WARNING, "The disable_classes INI setting has been removed and has no effect");
+
+	return FAILURE;
+}
+
 /* defined in browscap.c */
 PHP_INI_MH(OnChangeBrowscap);
 
@@ -757,7 +733,7 @@ PHP_INI_BEGIN()
 	PHP_INI_ENTRY("sendmail_path",	DEFAULT_SENDMAIL_PATH,	PHP_INI_SYSTEM,		NULL)
 	PHP_INI_ENTRY("mail.force_extra_parameters",NULL,		PHP_INI_SYSTEM|PHP_INI_PERDIR,		OnChangeMailForceExtra)
 	PHP_INI_ENTRY("disable_functions",			"",			PHP_INI_SYSTEM,		NULL)
-	PHP_INI_ENTRY("disable_classes",			"",			PHP_INI_SYSTEM,		NULL)
+	PHP_INI_ENTRY("disable_classes",			"",			PHP_INI_SYSTEM,		OnChangeDisableClasses)
 	PHP_INI_ENTRY("max_file_uploads",			"20",			PHP_INI_SYSTEM|PHP_INI_PERDIR,		NULL)
 	PHP_INI_ENTRY("max_multipart_body_parts",	"-1",			PHP_INI_SYSTEM|PHP_INI_PERDIR,		NULL)
 
@@ -1975,9 +1951,6 @@ static void core_globals_dtor(php_core_globals *core_globals)
 	ZEND_ASSERT(!core_globals->last_error_message);
 	ZEND_ASSERT(!core_globals->last_error_file);
 
-	if (core_globals->disable_classes) {
-		free(core_globals->disable_classes);
-	}
 	if (core_globals->php_binary) {
 		free(core_globals->php_binary);
 	}
@@ -2235,9 +2208,8 @@ zend_result php_module_startup(sapi_module_struct *sf, zend_module_entry *additi
 		}
 	}
 
-	/* disable certain classes and functions as requested by php.ini */
+	/* disable certain functions as requested by php.ini */
 	zend_disable_functions(INI_STR("disable_functions"));
-	php_disable_classes();
 
 	/* make core report what it should */
 	if ((module = zend_hash_str_find_ptr(&module_registry, "core", sizeof("core")-1)) != NULL) {
diff --git a/main/php_globals.h b/main/php_globals.h
index b2f2696c2db2c..bd2bd67e753e7 100644
--- a/main/php_globals.h
+++ b/main/php_globals.h
@@ -142,7 +142,6 @@ struct _php_core_globals {
 
 	char *php_sys_temp_dir;
 
-	char *disable_classes;
 	zend_long max_input_nesting_level;
 	zend_long max_input_vars;
 
diff --git a/main/php_version.h b/main/php_version.h
index 1cbfc9afcada9..4d24349b3e7d6 100644
--- a/main/php_version.h
+++ b/main/php_version.h
@@ -1,8 +1,8 @@
 /* automatically generated by configure */
 /* edit configure.ac to change version number */
 #define PHP_MAJOR_VERSION 8
-#define PHP_MINOR_VERSION 4
+#define PHP_MINOR_VERSION 3
 #define PHP_RELEASE_VERSION 0
 #define PHP_EXTRA_VERSION "-dev"
-#define PHP_VERSION "8.4.0-dev"
-#define PHP_VERSION_ID 80400
+#define PHP_VERSION "8.3.0-dev"
+#define PHP_VERSION_ID 80300
diff --git a/php.ini-development b/php.ini-development
index 2ce934f811932..099b2f8d91423 100644
--- a/php.ini-development
+++ b/php.ini-development
@@ -332,11 +332,6 @@ serialize_precision = -1
 ; https://php.net/disable-functions
 disable_functions =
 
-; This directive allows you to disable certain classes.
-; It receives a comma-delimited list of class names.
-; https://php.net/disable-classes
-disable_classes =
-
 ; Colors for Syntax Highlighting mode.  Anything that's acceptable in
 ; <span style="color: ???????"> would work.
 ; https://php.net/syntax-highlighting
diff --git a/php.ini-production b/php.ini-production
index 43d24fc372087..3108d18b8fa3f 100644
--- a/php.ini-production
+++ b/php.ini-production
@@ -332,11 +332,6 @@ serialize_precision = -1
 ; https://php.net/disable-functions
 disable_functions =
 
-; This directive allows you to disable certain classes.
-; It receives a comma-delimited list of class names.
-; https://php.net/disable-classes
-disable_classes =
-
 ; Colors for Syntax Highlighting mode.  Anything that's acceptable in
 ; <span style="color: ???????"> would work.
 ; https://php.net/syntax-highlighting
diff --git a/sapi/fpm/fpm/fpm_php.c b/sapi/fpm/fpm/fpm_php.c
index b88c47671a1ec..41f49f96a06ba 100644
--- a/sapi/fpm/fpm/fpm_php.c
+++ b/sapi/fpm/fpm/fpm_php.c
@@ -48,35 +48,6 @@ static int fpm_php_zend_ini_alter_master(char *name, int name_length, char *new_
 }
 /* }}} */
 
-static void fpm_php_disable(char *value, int (*zend_disable)(const char *, size_t)) /* {{{ */
-{
-	char *s = 0, *e = value;
-
-	while (*e) {
-		switch (*e) {
-			case ' ':
-			case ',':
-				if (s) {
-					*e = '\0';
-					zend_disable(s, e - s);
-					s = 0;
-				}
-				break;
-			default:
-				if (!s) {
-					s = e;
-				}
-				break;
-		}
-		e++;
-	}
-
-	if (s) {
-		zend_disable(s, e - s);
-	}
-}
-/* }}} */
-
 #define FPM_PHP_INI_ALTERING_ERROR   -1
 #define FPM_PHP_INI_APPLIED          1
 #define FPM_PHP_INI_EXTENSION_FAILED 0
@@ -107,13 +78,6 @@ int fpm_php_apply_defines_ex(struct key_value_s *kv, int mode) /* {{{ */
 		return FPM_PHP_INI_APPLIED;
 	}
 
-	if (!strcmp(name, "disable_classes") && *value) {
-		char *v = strdup(value);
-		PG(disable_classes) = v;
-		fpm_php_disable(v, zend_disable_class);
-		return FPM_PHP_INI_APPLIED;
-	}
-
 	return FPM_PHP_INI_APPLIED;
 }
 /* }}} */
diff --git a/sapi/fpm/www.conf.in b/sapi/fpm/www.conf.in
index ff47b50422c2f..14d3e1d48d711 100644
--- a/sapi/fpm/www.conf.in
+++ b/sapi/fpm/www.conf.in
@@ -474,9 +474,8 @@ pm.max_spare_servers = 3
 ; For php_*flag, valid values are on, off, 1, 0, true, false, yes or no.
 
 ; Defining 'extension' will load the corresponding shared extension from
-; extension_dir. Defining 'disable_functions' or 'disable_classes' will not
-; overwrite previously defined php.ini values, but will append the new value
-; instead.
+; extension_dir. Defining 'disable_functions' will not overwrite previously
+; defined php.ini values, but will append the new value instead.
 
 ; Note: path INI options can be relative and will be expanded with the prefix
 ; (pool, global or @prefix@)
diff --git a/sapi/fuzzer/fuzzer-json.c b/sapi/fuzzer/fuzzer-json.c
index 4335598bc3caa..8a8003aa50415 100644
--- a/sapi/fuzzer/fuzzer-json.c
+++ b/sapi/fuzzer/fuzzer-json.c
@@ -20,6 +20,7 @@
 #include "fuzzer.h"
 
 #include "Zend/zend.h"
+#include "main/php.h"
 #include "main/php_config.h"
 #include "main/php_main.h"
 
diff --git a/sapi/fuzzer/fuzzer-sapi.c b/sapi/fuzzer/fuzzer-sapi.c
index baf77ae0463b3..b052f174005b6 100644
--- a/sapi/fuzzer/fuzzer-sapi.c
+++ b/sapi/fuzzer/fuzzer-sapi.c
@@ -56,8 +56,6 @@ static const char HARDCODED_INI[] =
 	",crypt"
 	/* openlog() has a known memory-management issue. */
 	",openlog"
-	/* Can cause long loops that bypass the executor step limit. */
-	"\ndisable_classes=InfiniteIterator"
 ;
 
 static int startup(sapi_module_struct *sapi_module)
@@ -128,6 +126,21 @@ static sapi_module_struct fuzzer_module = {
 	STANDARD_SAPI_MODULE_PROPERTIES
 };
 
+static ZEND_COLD zend_object *disable_class_create_handler(zend_class_entry *class_type) /* {{{ */
+{
+	zend_throw_error(NULL, "Cannot construct class %s, as it is disabled", ZSTR_VAL(class_type->name));
+	return NULL;
+}
+
+static void fuzzer_disable_classes(void)
+{
+	/* Overwrite built-in constructor for InfiniteIterator as it
+	 * can cause long loops that bypass the executor step limit. */
+	/* Lowercase as this is how the CE as stored */
+	zend_class_entry *InfiniteIterator_class = zend_hash_str_find(CG(class_table), "infiniteiterator", strlen("infiniteiterator"));
+	InfiniteIterator_class->create_object = disable_class_create_handler;
+}
+
 int fuzzer_init_php(const char *extra_ini)
 {
 #ifdef __SANITIZE_ADDRESS__
@@ -183,6 +196,8 @@ int fuzzer_request_startup(void)
 	SIGG(check) = 0;
 #endif
 
+	fuzzer_disable_classes();
+
 	return SUCCESS;
 }
 
diff --git a/sapi/fuzzer/fuzzer-unserialize.c b/sapi/fuzzer/fuzzer-unserialize.c
index ff26e5b1e8da3..0e1f83bb6b694 100644
--- a/sapi/fuzzer/fuzzer-unserialize.c
+++ b/sapi/fuzzer/fuzzer-unserialize.c
@@ -18,6 +18,7 @@
 #include "fuzzer.h"
 
 #include "Zend/zend.h"
+#include "main/php.h"
 #include "main/php_config.h"
 #include "main/php_main.h"
 
diff --git a/sapi/fuzzer/fuzzer-unserializehash.c b/sapi/fuzzer/fuzzer-unserializehash.c
index 5d29eb5fb8c61..89326d3c7b50b 100644
--- a/sapi/fuzzer/fuzzer-unserializehash.c
+++ b/sapi/fuzzer/fuzzer-unserializehash.c
@@ -16,6 +16,7 @@
 #include "fuzzer.h"
 
 #include "Zend/zend.h"
+#include "main/php.h"
 #include "main/php_config.h"
 #include "main/php_main.h"