diff --git a/common.gypi b/common.gypi
index 64c70c83975bee..ba4966e435171c 100644
--- a/common.gypi
+++ b/common.gypi
@@ -29,7 +29,7 @@
 
     # Reset this number to 0 on major V8 upgrades.
     # Increment by one for each non-official patch applied to deps/v8.
-    'v8_embedder_string': '-node.20',
+    'v8_embedder_string': '-node.21',
 
     # Enable disassembler for `--print-code` v8 options
     'v8_enable_disassembler': 1,
diff --git a/deps/v8/include/v8.h b/deps/v8/include/v8.h
index 91001cf594ca26..b5befd51573e30 100644
--- a/deps/v8/include/v8.h
+++ b/deps/v8/include/v8.h
@@ -2634,20 +2634,25 @@ class V8_EXPORT String : public Name {
   };
 
   // 16-bit character codes.
-  int Write(uint16_t* buffer,
-            int start = 0,
-            int length = -1,
+  int Write(Isolate* isolate, uint16_t* buffer, int start = 0, int length = -1,
             int options = NO_OPTIONS) const;
+  V8_DEPRECATE_SOON("Use Isolate* version",
+                    int Write(uint16_t* buffer, int start = 0, int length = -1,
+                              int options = NO_OPTIONS) const);
   // One byte characters.
-  int WriteOneByte(uint8_t* buffer,
-                   int start = 0,
-                   int length = -1,
-                   int options = NO_OPTIONS) const;
+  int WriteOneByte(Isolate* isolate, uint8_t* buffer, int start = 0,
+                   int length = -1, int options = NO_OPTIONS) const;
+  V8_DEPRECATE_SOON("Use Isolate* version",
+                    int WriteOneByte(uint8_t* buffer, int start = 0,
+                                     int length = -1, int options = NO_OPTIONS)
+                        const);
   // UTF-8 encoded characters.
-  int WriteUtf8(char* buffer,
-                int length = -1,
-                int* nchars_ref = NULL,
-                int options = NO_OPTIONS) const;
+  int WriteUtf8(Isolate* isolate, char* buffer, int length = -1,
+                int* nchars_ref = NULL, int options = NO_OPTIONS) const;
+  V8_DEPRECATE_SOON("Use Isolate* version",
+                    int WriteUtf8(char* buffer, int length = -1,
+                                  int* nchars_ref = NULL,
+                                  int options = NO_OPTIONS) const);
 
   /**
    * A zero length string.
diff --git a/deps/v8/src/api.cc b/deps/v8/src/api.cc
index a2721f180e20a9..191acb80aac8c2 100644
--- a/deps/v8/src/api.cc
+++ b/deps/v8/src/api.cc
@@ -5702,12 +5702,10 @@ static bool RecursivelySerializeToUtf8(i::String* current,
 }
 
 
-int String::WriteUtf8(char* buffer,
-                      int capacity,
-                      int* nchars_ref,
-                      int options) const {
+int String::WriteUtf8(Isolate* v8_isolate, char* buffer, int capacity,
+                      int* nchars_ref, int options) const {
   i::Handle<i::String> str = Utils::OpenHandle(this);
-  i::Isolate* isolate = str->GetIsolate();
+  i::Isolate* isolate = reinterpret_cast<i::Isolate*>(v8_isolate);
   LOG_API(isolate, String, WriteUtf8);
   ENTER_V8_NO_SCRIPT_NO_EXCEPTION(isolate);
   str = i::String::Flatten(str);  // Flatten the string for efficiency.
@@ -5748,14 +5746,18 @@ int String::WriteUtf8(char* buffer,
   return writer.CompleteWrite(write_null, nchars_ref);
 }
 
+int String::WriteUtf8(char* buffer, int capacity, int* nchars_ref,
+                      int options) const {
+  i::Handle<i::String> str = Utils::OpenHandle(this);
+  i::Isolate* isolate = str->GetIsolate();
+  return WriteUtf8(reinterpret_cast<Isolate*>(isolate), buffer, capacity,
+                   nchars_ref, options);
+}
 
-template<typename CharType>
-static inline int WriteHelper(const String* string,
-                              CharType* buffer,
-                              int start,
-                              int length,
+template <typename CharType>
+static inline int WriteHelper(i::Isolate* isolate, const String* string,
+                              CharType* buffer, int start, int length,
                               int options) {
-  i::Isolate* isolate = Utils::OpenHandle(string)->GetIsolate();
   LOG_API(isolate, String, Write);
   ENTER_V8_NO_SCRIPT_NO_EXCEPTION(isolate);
   DCHECK(start >= 0 && length >= -1);
@@ -5778,7 +5780,14 @@ int String::WriteOneByte(uint8_t* buffer,
                          int start,
                          int length,
                          int options) const {
-  return WriteHelper(this, buffer, start, length, options);
+  i::Isolate* isolate = Utils::OpenHandle(this)->GetIsolate();
+  return WriteHelper(isolate, this, buffer, start, length, options);
+}
+
+int String::WriteOneByte(Isolate* isolate, uint8_t* buffer, int start,
+                         int length, int options) const {
+  return WriteHelper(reinterpret_cast<i::Isolate*>(isolate), this, buffer,
+                     start, length, options);
 }
 
 
@@ -5786,7 +5795,14 @@ int String::Write(uint16_t* buffer,
                   int start,
                   int length,
                   int options) const {
-  return WriteHelper(this, buffer, start, length, options);
+  i::Isolate* isolate = Utils::OpenHandle(this)->GetIsolate();
+  return WriteHelper(isolate, this, buffer, start, length, options);
+}
+
+int String::Write(Isolate* isolate, uint16_t* buffer, int start, int length,
+                  int options) const {
+  return WriteHelper(reinterpret_cast<i::Isolate*>(isolate), this, buffer,
+                     start, length, options);
 }