Changed from deprecated .Site.LanguageCode to .Site.Language.Locale

layouts/_default/rss.xml

@@ -17,7 +17,7 @@
     <link>{{ .Permalink }}</link>
     <description>Recent content {{ if ne  .Title  .Site.Title }}{{ with .Title }}in {{.}} {{ end }}{{ end }}on {{ .Site.Title }}</description>
     <generator>Hugo -- gohugo.io</generator>
-    <language>{{ site.LanguageCode }}</language>{{ with .Site.Params.Author.email }}
+    <language>{{ site.Language.Locale }}</language>{{ with .Site.Params.Author.email }}
     <managingEditor>{{.}}{{ with $.Site.Params.Author.name }} ({{.}}){{end}}</managingEditor>{{end}}{{ with .Site.Params.Author.email }}
     <webMaster>{{.}}{{ with $.Site.Params.Author.name }} ({{.}}){{end}}</webMaster>{{end}}
     {{ if .Site.Params.footer.showCopyright | default true -}}

layouts/_default/sitemap.xml

@@ -15,7 +15,7 @@
     />{{ end }}
     <xhtml:link
       rel="alternate"
-      hreflang="{{ .Language.LanguageCode }}"
+      hreflang="{{ .Language.Locale }}"
       href="{{ $link }}"
     />{{ end }}
   </url>