diff --git a/config/schema/fillpdf.schema.yml b/config/schema/fillpdf.schema.yml
index c4b27a81eb78e0e32a03e218f769010bc0b1c6a4..117a3eafea4a33caba8e57a392ce634ee6a1f10b 100644
--- a/config/schema/fillpdf.schema.yml
+++ b/config/schema/fillpdf.schema.yml
@@ -11,6 +11,9 @@ fillpdf.settings:
     remote_endpoint:
       type: string
       label: 'FillPDF Service endpoint URL without protocol'
+    fillpdf_service:
+      type: string
+      label: 'Which PDF filling backend to use'
     fillpdf_service_api_key:
       type: string
       label: 'FillPDF Service API key'
@@ -26,6 +29,9 @@ fillpdf.settings:
     local_service_endpoint:
       type: string
       label: 'Local FillPDF PDF API endpoint'
+    pdftk_path:
+      type: string
+      label: 'Path to the pdftk command'
     shell_locale:
       type: string
       label: 'Locale for escaping shell commands'