diff --git a/Dockerfile b/Dockerfile
index 85738f4..9b3ec61 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -9,6 +9,8 @@ ARG DUCKDNS_VERSION
 LABEL build_version="Linuxserver.io version:- ${VERSION} Build-date:- ${BUILD_DATE}"
 LABEL maintainer="aptalca"
 
+ENV UPDATE_IP=ipv4
+
 RUN \
   echo "**** install packages ****" && \
   apk add --no-cache \
diff --git a/Dockerfile.aarch64 b/Dockerfile.aarch64
index ef78e59..3622a28 100644
--- a/Dockerfile.aarch64
+++ b/Dockerfile.aarch64
@@ -9,6 +9,8 @@ ARG DUCKDNS_VERSION
 LABEL build_version="Linuxserver.io version:- ${VERSION} Build-date:- ${BUILD_DATE}"
 LABEL maintainer="aptalca"
 
+ENV UPDATE_IP=ipv4
+
 RUN \
   echo "**** install packages ****" && \
   apk add --no-cache \
diff --git a/readme-vars.yml b/readme-vars.yml
index 076b23b..fd82e21 100644
--- a/readme-vars.yml
+++ b/readme-vars.yml
@@ -39,7 +39,7 @@ cap_add_param_vars: ""
 # optional container parameters
 opt_param_usage_include_env: true
 opt_param_env_vars:
-  - { env_var: "FORCE_IPV6", env_value: "false", desc: "Set to `true` to update IP **only** with your public IPv6 address. NB: use only if you have a public IPv6 address."}
+  - { env_var: "UPDATE_IP", env_value: "ipv4", desc: "Set to `ipv6` to update  **only** with your public IPv6 address. Set to `both` to update IPv6 and IPv4 address. Default to `ipv4`"}
   - { env_var: "LOG_FILE", env_value: "false", desc: "Set to `true` to log to file (also need to map /config)."}
 opt_param_usage_include_vols: true
 opt_param_volumes:
diff --git a/root/app/duck.sh b/root/app/duck.sh
index ca1350c..747c708 100755
--- a/root/app/duck.sh
+++ b/root/app/duck.sh
@@ -11,10 +11,14 @@ else
 fi
 
 {
-    if [ "${FORCE_IPV6}" = "true" ]; then
+    if [ "${UPDATE_IP}" = "both" ]; then
+        IPV4=$(curl -sS4 "https://ipconfig.io")
+        IPV6=$(curl -sS6 "https://ipconfig.io")
+        RESPONSE=$(curl -sS --max-time 60 "https://www.duckdns.org/update?domains=${SUBDOMAINS}&token=${TOKEN}&ip=${IPV4}&ipv6=${IPV6}")
+    elif [ "${UPDATE_IP}" = "ipv6" ]; then
         IPV6=$(curl -sS6 "https://ipconfig.io")
         RESPONSE=$(curl -sS --max-time 60 "https://www.duckdns.org/update?domains=${SUBDOMAINS}&token=${TOKEN}&ip=${IPV6}")
-    else
+    elif [ "${UPDATE_IP}" = "ipv4" ]; then
         RESPONSE=$(curl -sS --max-time 60 "https://www.duckdns.org/update?domains=${SUBDOMAINS}&token=${TOKEN}&ip=")
     fi