diff -r e381e2624077 -r 2136e4670ad2 src/HOL/Proofs/ex/XML_Data.thy
--- a/src/HOL/Proofs/ex/XML_Data.thy	Fri Oct 11 21:44:39 2019 +0200
+++ b/src/HOL/Proofs/ex/XML_Data.thy	Fri Oct 11 21:51:10 2019 +0200
@@ -13,7 +13,8 @@
 
 ML \<open>
   fun export_proof thy thm =
-    Proofterm.encode (Sign.consts_of thy) (Thm.clean_proof_of true thm);
+    Proofterm.encode (Sign.consts_of thy)
+      (Proofterm.reconstruct_proof thy (Thm.prop_of thm) (Thm.standard_proof_of true thm));
 
   fun import_proof thy xml =
     let