diff --git a/proto/invoice/invoice.proto b/proto/invoice/invoice.proto
index 187e358..a5c6a84 100644
--- a/proto/invoice/invoice.proto
+++ b/proto/invoice/invoice.proto
@@ -29,10 +29,13 @@
     string customer_vat_id = 6;
     bool reverse_vat = 7;
     bool us_customer = 11;
+    // Optional, if not given the proforma will be created with the current time.
+    int64 date = 14;
     int64 days_due = 8;
     string iban = 9;
     string swift = 10;
     string unit = 13;
+    // Next tag: 15
 }
 
 message Invoice {
@@ -74,6 +77,7 @@
 
 message RenderInvoiceRequest {
     string uid = 1;
+    string language = 2;
 }
 
 message RenderInvoiceResponse {
@@ -82,6 +86,12 @@
 
 message SealInvoiceRequest {
     string uid = 1;
+    enum DateSource {
+        DATE_SOURCE_NOW = 0;
+        DATE_SOURCE_PROFORMA = 1;
+    }
+    DateSource date_source = 2;
+    string language = 3;
 }
 
 message SealInvoiceResponse {