diff --git a/docs/source/about/advanced_usage.rst b/docs/source/about/advanced_usage.rst
index d23b96cc58..36468fd125 100644
--- a/docs/source/about/advanced_usage.rst
+++ b/docs/source/about/advanced_usage.rst
@@ -63,8 +63,8 @@ editing the `conf` file in a text editor. Use the examples as reference.
======= ===========
de German
en English
- en-GB English (UK)
- en-US English (United States)
+ en_GB English (UK)
+ en_US English (United States)
es Spanish
fr French
it Italian
diff --git a/src/config.cpp b/src/config.cpp
index b2660f7d2c..fd36c67295 100644
--- a/src/config.cpp
+++ b/src/config.cpp
@@ -1105,8 +1105,8 @@ namespace config {
string_restricted_f(vars, "locale", config::sunshine.locale, {
"de"sv, // German
"en"sv, // English
- "en-GB"sv, // English (UK)
- "en-US"sv, // English (US)
+ "en_GB"sv, // English (UK)
+ "en_US"sv, // English (US)
"es"sv, // Spanish
"fr"sv, // French
"it"sv, // Italian
diff --git a/src_assets/common/assets/web/config.html b/src_assets/common/assets/web/config.html
index 963464d2fe..9161df43e3 100644
--- a/src_assets/common/assets/web/config.html
+++ b/src_assets/common/assets/web/config.html
@@ -43,8 +43,8 @@