diff -r 87d095351f8e -r 29cba276be23 src/HOL/Mutabelle/lib/Tools/mutabelle
--- a/src/HOL/Mutabelle/lib/Tools/mutabelle	Sat Nov 08 20:06:42 2025 +0100
+++ b/src/HOL/Mutabelle/lib/Tools/mutabelle	Sat Nov 08 20:16:08 2025 +0100
@@ -133,8 +133,8 @@
 
 # execution
 
-isabelle process -o auto_time_limit=10.0 \
-  -T "$MUTABELLE_OUTPUT_PATH/Mutabelle_Test" -l "$MUTABELLE_LOGIC" > "$MUTABELLE_OUTPUT_PATH/err" 2>&1
+isabelle ML_process -o auto_time_limit=10.0 \
+  -e "Thy_Info.use_thy_legacy \"$MUTABELLE_OUTPUT_PATH/Mutabelle_Test\"" -l "$MUTABELLE_LOGIC" > "$MUTABELLE_OUTPUT_PATH/err" 2>&1
 
 
 [ $? -ne 0 ] && echo "isabelle processing of mutabelle failed"