System.NotSupportedException: Unknown language 'mjs', Supported languages: csharp, typescript, dart, java, kotlin, python, swift, vbnet, fsharp at ServiceStack.NativeTypes.LangGeneratorExtensions.GenerateSourceCode(MetadataTypes metadataTypes, MetadataTypesConfig typesConfig, String lang, IRequest req, Action`1 configure) in /home/runner/work/ServiceStack/ServiceStack/ServiceStack/src/ServiceStack/NativeTypes/ILangGenerator.cs:line 53 at ServiceStack.NativeTypes.LangGeneratorExtensions.GenerateSourceCode(List`1 metadataTypes, String lang, IRequest req, Action`1 configure) in /home/runner/work/ServiceStack/ServiceStack/ServiceStack/src/ServiceStack/NativeTypes/ILangGenerator.cs:line 26 at ServiceStack.Metadata.BaseMetadataHandler.d__12.MoveNext() in /home/runner/work/ServiceStack/ServiceStack/ServiceStack/src/ServiceStack/Metadata/BaseMetadataHandler.cs:line 207 
To override the Content-type in your clients, use the HTTP Accept Header, append the .xml suffix or ?format=xml
The following are sample HTTP requests and responses. The placeholders shown need to be replaced with actual values.
POST /xml/reply/DataStoreRequest HTTP/1.1 
Host: api.paysecure.acculynk.net 
Accept: application/xml
Content-Type: application/xml
Content-Length: length
<DataStoreRequest xmlns:i="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://schemas.servicestack.net/types">
  <Credentials>
    <MerchantId>String</MerchantId>
    <Password>String</Password>
    <UserName>String</UserName>
    <Version>String</Version>
  </Credentials>
  <Scope>
    <StoreScope>AllMerchants</StoreScope>
    <Value>String</Value>
  </Scope>
</DataStoreRequest>
HTTP/1.1 200 OK Content-Type: application/xml Content-Length: length <DataStore xmlns:i="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://schemas.servicestack.net/types"> <ErrorCode>String</ErrorCode> <ErrorMessage>String</ErrorMessage> </DataStore>