diff --git a/postfix/files/mapping.j2 b/postfix/files/mapping.j2
index 348ab4d..1e564c6 100644
--- a/postfix/files/mapping.j2
+++ b/postfix/files/mapping.j2
@@ -15,7 +15,7 @@
 {%- endmacro %}
 
 {%- if data is mapping %}
-{% for key, value in data.iteritems() %}
+{% for key, value in data.items() %}
 {{ format_value(key, value) }}
 {%- endfor -%}
 {%- else %}