diff --git a/NEWS b/NEWS
index 855bebdb0..9826552c3 100644
--- a/NEWS
+++ b/NEWS
@@ -17,6 +17,7 @@ Bug fixes
  - fixed freebusy data when 'busy off hours' is enabled and period starts during the weekend
  - fixed fetching of freebusy data from the Web interface
  - fixed EAS handling of Bcc in emails (#3138)
+ - fixed Language-Region tags in Web interface (#3121)
 
 2.2.16 (2015-02-12)
 -------------------
diff --git a/UI/MailerUI/UIxMailEditor.m b/UI/MailerUI/UIxMailEditor.m
index 80c29f512..7931bee13 100644
--- a/UI/MailerUI/UIxMailEditor.m
+++ b/UI/MailerUI/UIxMailEditor.m
@@ -230,7 +230,9 @@ static NSArray *infoKeys = nil;
 - (NSString *) localeCode
 {
   // WARNING : NSLocaleCode is not defined in <Foundation/NSUserDefaults.h>
-  return [locale objectForKey: @"NSLocaleCode"];
+  // Region subtag must be separated by a dash
+  NSString *s = [locale objectForKey: @"NSLocaleCode"];
+  return [s stringByReplacingOccurrencesOfString: @"_" withString: @"-"];
 }
 
 - (void) setFrom: (NSString *) newFrom
diff --git a/UI/Scheduler/UIxCalMainView.m b/UI/Scheduler/UIxCalMainView.m
index f9fd125eb..78d4723c6 100644
--- a/UI/Scheduler/UIxCalMainView.m
+++ b/UI/Scheduler/UIxCalMainView.m
@@ -82,7 +82,9 @@
 - (NSString *) localeCode
 {
   // WARNING : NSLocaleCode is not defined in <Foundation/NSUserDefaults.h>
-  return [locale objectForKey: @"NSLocaleCode"];
+  // Region subtag must be separated by a dash
+  NSString *s = [locale objectForKey: @"NSLocaleCode"];
+  return [s stringByReplacingOccurrencesOfString: @"_" withString: @"-"];
 }
 
 - (NSArray *) monthMenuItems