diff --git a/exampleYmlFiles/docker-compose-latest-lite-security.yml b/exampleYmlFiles/docker-compose-latest-lite-security.yml
index 41dc4567..90e4c5bf 100644
--- a/exampleYmlFiles/docker-compose-latest-lite-security.yml
+++ b/exampleYmlFiles/docker-compose-latest-lite-security.yml
@@ -21,7 +21,7 @@ services:
     environment:
       DOCKER_ENABLE_SECURITY: "true"
       SECURITY_ENABLELOGIN: "true"
-      SYSTEM_DEFAULTLOCALE: en_US
+      SYSTEM_DEFAULTLOCALE: en-US
       UI_APPNAME: Stirling-PDF-Lite
       UI_HOMEDESCRIPTION: Demo site for Stirling-PDF-Lite Latest with Security
       UI_APPNAMENAVBAR: Stirling-PDF-Lite Latest
diff --git a/exampleYmlFiles/docker-compose-latest-lite.yml b/exampleYmlFiles/docker-compose-latest-lite.yml
index 7b374688..e40f873d 100644
--- a/exampleYmlFiles/docker-compose-latest-lite.yml
+++ b/exampleYmlFiles/docker-compose-latest-lite.yml
@@ -20,7 +20,7 @@ services:
     environment:
       DOCKER_ENABLE_SECURITY: "false"
       SECURITY_ENABLELOGIN: "false"
-      SYSTEM_DEFAULTLOCALE: en_US
+      SYSTEM_DEFAULTLOCALE: en-US
       UI_APPNAME: Stirling-PDF-Lite
       UI_HOMEDESCRIPTION: Demo site for Stirling-PDF-Lite Latest
       UI_APPNAMENAVBAR: Stirling-PDF-Lite Latest
diff --git a/exampleYmlFiles/docker-compose-latest-security.yml b/exampleYmlFiles/docker-compose-latest-security.yml
index 807a755e..513bb582 100644
--- a/exampleYmlFiles/docker-compose-latest-security.yml
+++ b/exampleYmlFiles/docker-compose-latest-security.yml
@@ -21,7 +21,7 @@ services:
     environment:
       DOCKER_ENABLE_SECURITY: "true"
       SECURITY_ENABLELOGIN: "true"
-      SYSTEM_DEFAULTLOCALE: en_US
+      SYSTEM_DEFAULTLOCALE: en-US
       UI_APPNAME: Stirling-PDF
       UI_HOMEDESCRIPTION: Demo site for Stirling-PDF Latest with Security
       UI_APPNAMENAVBAR: Stirling-PDF Latest
diff --git a/exampleYmlFiles/docker-compose-latest-ultra-lite-security.yml b/exampleYmlFiles/docker-compose-latest-ultra-lite-security.yml
index 7971eeb7..b7848696 100644
--- a/exampleYmlFiles/docker-compose-latest-ultra-lite-security.yml
+++ b/exampleYmlFiles/docker-compose-latest-ultra-lite-security.yml
@@ -21,7 +21,7 @@ services:
     environment:
       DOCKER_ENABLE_SECURITY: "true"
       SECURITY_ENABLELOGIN: "true"
-      SYSTEM_DEFAULTLOCALE: en_US
+      SYSTEM_DEFAULTLOCALE: en-US
       UI_APPNAME: Stirling-PDF-Lite
       UI_HOMEDESCRIPTION: Demo site for Stirling-PDF-Lite Latest with Security
       UI_APPNAMENAVBAR: Stirling-PDF-Lite Latest
diff --git a/exampleYmlFiles/docker-compose-latest-ultra-lite.yml b/exampleYmlFiles/docker-compose-latest-ultra-lite.yml
index 31fec67b..710c0072 100644
--- a/exampleYmlFiles/docker-compose-latest-ultra-lite.yml
+++ b/exampleYmlFiles/docker-compose-latest-ultra-lite.yml
@@ -20,7 +20,7 @@ services:
     environment:
       DOCKER_ENABLE_SECURITY: "false"
       SECURITY_ENABLELOGIN: "false"
-      SYSTEM_DEFAULTLOCALE: en_US
+      SYSTEM_DEFAULTLOCALE: en-US
       UI_APPNAME: Stirling-PDF-Ultra-lite
       UI_HOMEDESCRIPTION: Demo site for Stirling-PDF-Ultra-lite Latest
       UI_APPNAMENAVBAR: Stirling-PDF-Ultra-lite Latest
diff --git a/exampleYmlFiles/docker-compose-latest.yml b/exampleYmlFiles/docker-compose-latest.yml
index a9dc1f31..d506e424 100644
--- a/exampleYmlFiles/docker-compose-latest.yml
+++ b/exampleYmlFiles/docker-compose-latest.yml
@@ -21,7 +21,7 @@ services:
     environment:
       DOCKER_ENABLE_SECURITY: "false"
       SECURITY_ENABLELOGIN: "false"
-      SYSTEM_DEFAULTLOCALE: en_US
+      SYSTEM_DEFAULTLOCALE: en-US
       UI_APPNAME: Stirling-PDF
       UI_HOMEDESCRIPTION: Demo site for Stirling-PDF Latest
       UI_APPNAMENAVBAR: Stirling-PDF Latest