diff --git a/src/config.h b/src/config.h
index 62f1a0c6..0c407b6a 100644
--- a/src/config.h
+++ b/src/config.h
@@ -131,10 +131,11 @@
 
 #define FNGPRINT    0
 #define CERTIFICATE 1
+#define IASLIB      "2.1.0-RC3"
 
 // used for storing the config struct to eeprom
-#define MAGICBYTES                  "CFG"
-#define MAGICEEP                    "%"
+#define MAGICBYTES  "CFG"
+#define MAGICEEP    "%"
 
 #if WIFI_DHCP_ONLY == false && WIFI_MULTI == true
     #undef WIFI_MULTI
diff --git a/src/espressif/esp32/CallServer.cpp b/src/espressif/esp32/CallServer.cpp
index 89e82eca..a001c2b1 100644
--- a/src/espressif/esp32/CallServer.cpp
+++ b/src/espressif/esp32/CallServer.cpp
@@ -234,6 +234,7 @@ bool CallServer::get(const char* url, String args) {
                F("\r\nx-ESP-FLASHCHIP-ID: ") + ESP_GETFLASHCHIPID +
                F("\r\nx-ESP-CHIP-ID: ") + ESP_GETCHIPID +
                F("\r\nx-ESP-CORE-VERSION: ") + ESP.getSdkVersion() +
+               F("\r\nx-ESP_IASLIB: ") + IASLIB +
 
                F("\r\nx-ESP-FLASHCHIP-SIZE: ") + ESP.getFlashChipSize() +
                F("\r\nx-ESP-VERSION: ") + this->_config->appName + " v" + this->_config->appVersion +
diff --git a/src/espressif/esp8266/CallServer.cpp b/src/espressif/esp8266/CallServer.cpp
index 002308fd..0380d114 100644
--- a/src/espressif/esp8266/CallServer.cpp
+++ b/src/espressif/esp8266/CallServer.cpp
@@ -259,6 +259,7 @@ bool CallServer::get(const char* url, String args) {
                F("\r\nx-ESP-FLASHCHIP-ID: ") + ESP_GETFLASHCHIPID +
                F("\r\nx-ESP-CHIP-ID: ") + ESP_GETCHIPID +
                F("\r\nx-ESP-CORE-VERSION: ") + ESP.getCoreVersion() +
+               F("\r\nx-ESP_IASLIB: ") + IASLIB +
 
                F("\r\nx-ESP-FLASHCHIP-SIZE: ") + ESP.getFlashChipSize() +
                F("\r\nx-ESP-VERSION: ") + this->_config->appName + " v" + this->_config->appVersion +