diff --git a/kefiya/utils/fints_controller_legacy.py b/kefiya/utils/fints_controller_legacy.py
index 10d5351..b92501f 100644
--- a/kefiya/utils/fints_controller_legacy.py
+++ b/kefiya/utils/fints_controller_legacy.py
@@ -237,14 +237,38 @@ def import_fints_transactions(self, kefiya_import):
 
                 # curr_doc.start_date = tansactions[0]["date"]
                 # curr_doc.end_date = tansactions[-1]["date"]
-                first_txn = tansactions[0][0]
-                last_txn = tansactions[0][-1]
+                # PATCH: tansactions kann verschachtelt oder flach sein - normalisieren
+if tansactions and isinstance(tansactions[0], list):
+    flat = []
+    for entry in tansactions:
+        if isinstance(entry, list):
+            flat.extend(entry)
+        else:
+            flat.append(entry)
+    tansactions = flat
+
+# PATCH: Debug-Log fuer Diagnose (kann spaeter entfernt werden)
+try:
+    frappe.log_error(
+        title="Kefiya FinTS Debug",
+        message="Count={} Type={} Sample={}".format(
+            len(tansactions),
+            type(tansactions[0]).__name__ if tansactions else 'N/A',
+            str(tansactions[0])[:500] if tansactions else 'empty'
+        )
+    )
+except Exception:
+    pass
+
+first_txn = tansactions[0]
+last_txn = tansactions[-1]
 
-                curr_doc.start_date = first_txn.get("date") or first_txn.get("ValueDate.Date")
-                curr_doc.end_date   = last_txn.get("date") or last_txn.get("ValueDate.Date")
+curr_doc.start_date = first_txn.get("date") or first_txn.get("ValueDate.Date")
+curr_doc.end_date   = last_txn.get("date") or last_txn.get("ValueDate.Date")
 
-                importer = ImportBankTransaction(self.kefiya_login, self.interactive)
-                importer.kefiya_import(tansactions)
+importer = ImportBankTransaction(self.kefiya_login, self.interactive)
+# PATCH: old_kefiya_import statt kefiya_import - MT940-Format-Handler fuer FinTS
+importer.old_kefiya_import(tansactions)
 
                 if len(importer.bank_transactions) == 0:
                     frappe.msgprint(_("No new payments found"))
diff --git a/pyproject.toml b/pyproject.toml
new file mode 100644
index 0000000..cbdc322
--- /dev/null
+++ b/pyproject.toml
@@ -0,0 +1,19 @@
+[project]
+name = "kefiya"
+authors = [
+    { name = "Phamos GmbH", email = "info@phamos.eu" },
+]
+description = "FinTS Connector for ERPNext (Germany)"
+requires-python = ">=3.10"
+readme = "README.md"
+dynamic = ["version"]
+dependencies = [
+    "fints==5.0.0b1"
+]
+
+[build-system]
+requires = ["flit_core >=3.4,<4"]
+build-backend = "flit_core.buildapi"
+
+[tool.flit.module]
+name = "kefiya"