Use StringSymbolOrProcSetting for footer.

Author: varyonic

lib/active_admin/namespace_settings.rb

@@ -18,7 +18,7 @@ class NamespaceSettings < DynamicSettingsNode
     register :site_title_image, "", :string_symbol_or_proc
 
     # Set the site footer text (defaults to Powered by ActiveAdmin text with version)
-    register :footer, ""
+    register :footer, "", :string_symbol_or_proc
 
     # Set a favicon
     register :favicon, false

lib/active_admin/views/footer.rb

@@ -6,21 +6,17 @@ def build(namespace)
         super id: "footer"
         @namespace = namespace
 
-        if footer?
+        if footer_text.present?
           para footer_text
         else
           para powered_by_message
         end
       end
 
-      def footer?
-        @namespace.footer.present?
-      end
-
       private
 
       def footer_text
-        helpers.render_or_call_method_or_proc_on(self, @namespace.footer)
+        @footer_text ||= @namespace.footer(self)
       end
 
       def powered_by_message