diff --git a/library.json b/library.json
index bc57fdd..e09f34c 100644
--- a/library.json
+++ b/library.json
@@ -1,6 +1,6 @@
 {
   "name": "ESP Mail Client",
-  "version": "3.4.19",
+  "version": "3.4.20",
   "keywords": "communication, email, imap, smtp, esp32, esp8266, samd, arduino",
   "description": "Arduino E-Mail Client Library to send, read and get incoming email notification for ESP32, ESP8266 and SAMD21 devices. The library also supported other Arduino Devices using Clients interfaces e.g. WiFiClient, EthernetClient, and GSMClient.",
   "repository": {
@@ -12,5 +12,5 @@
     "email": "suwatchai@outlook.com"
   }],
   "frameworks": "arduino",
-  "platforms": "espressif32, espressif8266, atmelsam, atmelavr, atmelmegaavr, ststm32, teensy, rp2040"
+  "platforms": "espressif32, espressif8266, atmelsam, atmelavr, atmelmegaavr, ststm32, teensy, rp2040, renesas-ra"
 }
diff --git a/library.properties b/library.properties
index b94ef44..007b262 100644
--- a/library.properties
+++ b/library.properties
@@ -1,6 +1,6 @@
 name=ESP Mail Client
 
-version=3.4.19
+version=3.4.20
 
 author=Mobizt
 
@@ -14,4 +14,4 @@ category=Communication
 
 url=https://github.com/mobizt/ESP-Mail-Client
 
-architectures=esp8266,esp32,sam,samd,stm32,STM32F1,STM32F4,teensy,avr,megaavr,mbed_nano,mbed_rp2040,rp2040
+architectures=esp8266,esp32,sam,samd,stm32,STM32F1,STM32F4,teensy,avr,megaavr,mbed_nano,mbed_rp2040,rp2040, renesas_uno
diff --git a/src/ESP_Mail_Client.cpp b/src/ESP_Mail_Client.cpp
index 8898af3..179f1d7 100644
--- a/src/ESP_Mail_Client.cpp
+++ b/src/ESP_Mail_Client.cpp
@@ -3,11 +3,10 @@
 
 #pragma GCC diagnostic ignored "-Wunused-but-set-variable"
 
-
 /**
  * Mail Client Arduino Library for Arduino devices.
  *
- * Created September 13, 2023
+ * Created July 15, 2024
  *
  * This library allows Espressif's ESP32, ESP8266, SAMD and RP2040 Pico devices to send and read Email through the SMTP and IMAP servers.
  *
@@ -796,13 +795,20 @@ void ESP_Mail_Client::appendHeaderField(MB_String &buf, const char *name, PGM_P
 
 void ESP_Mail_Client::appendAddressHeaderField(MB_String &buf, esp_mail_address_info_t &source, esp_mail_rfc822_header_field_types type, bool header, bool comma, bool newLine, bool encode)
 {
+
+  yield_impl();
+
   // Construct header field.
   if (header)
     appendHeaderName(buf, rfc822_headers[type].text);
 
-  if (type != esp_mail_rfc822_header_field_cc && type != esp_mail_rfc822_header_field_bcc &&
-      source.name.length() > 0)
+  if (type != esp_mail_rfc822_header_field_cc && type != esp_mail_rfc822_header_field_bcc && source.name.length() > 0)
   {
+    if (comma)
+      buf += esp_mail_str_8; /* "," */
+
+    comma = false;
+
     appendString(buf, encode ? encodeBUTF8(source.name.c_str()).c_str() : source.name.c_str(), false, false, esp_mail_string_mark_type_double_quote);
     // Add white space after name for SMTP to fix iCloud Mail Service IMAP search compatibility issue #278
     // This is not restricted by rfc2822.
diff --git a/src/ESP_Mail_Client.h b/src/ESP_Mail_Client.h
index dec0059..41cc34a 100644
--- a/src/ESP_Mail_Client.h
+++ b/src/ESP_Mail_Client.h
@@ -5,7 +5,7 @@
 /**
  * Mail Client Arduino Library for Arduino devices.
  *
- * Created September 13, 2023
+ * Created July 15, 2024
  *
  * This library allows Espressif's ESP32, ESP8266, SAMD and RP2040 Pico devices to send and read Email through the SMTP and IMAP servers.
  *
diff --git a/src/ESP_Mail_Client_Version.h b/src/ESP_Mail_Client_Version.h
index 8fa2c56..dc2c27a 100644
--- a/src/ESP_Mail_Client_Version.h
+++ b/src/ESP_Mail_Client_Version.h
@@ -3,8 +3,8 @@
 
 #ifndef ESP_MAIL_VERSION
 
-#define ESP_MAIL_VERSION "3.4.19"
-#define ESP_MAIL_VERSION_NUM 30419
+#define ESP_MAIL_VERSION "3.4.20"
+#define ESP_MAIL_VERSION_NUM 30420
 
 /* The inconsistent file version checking to prevent mixed versions compilation. */
 //#define VALID_VERSION_CHECK(ver) (ver == ESP_MAIL_VERSION_NUM)