diff --git a/app/modules/documents/local_agent_runtime/erp_local_agent/accounting_store.py b/app/modules/documents/local_agent_runtime/erp_local_agent/accounting_store.py
index 7e5a068..90c22c0 100644
--- a/app/modules/documents/local_agent_runtime/erp_local_agent/accounting_store.py
+++ b/app/modules/documents/local_agent_runtime/erp_local_agent/accounting_store.py
@@ -227,6 +227,172 @@ class LocalAccountingStore:
     def exists(self, client_id: int) -> bool:
         return self.db_path(client_id).is_file()
 
+
+    # HISTORICAL_ACT_SCHEMA_AUTO_UPGRADE_V1
+    def _ensure_historical_schema_compatibility(
+        self,
+        client_id: int,
+        db: sqlite3.Connection,
+        current_path: Path,
+    ) -> None:
+        """Add missing Accounting Mirror tables/indexes to an older FY .act file.
+
+        Older financial-year mirrors can predate newer Accounting/Tally schema
+        objects. The current FY mirror for the same client is used only as a
+        schema reference. Existing rows/tables are never dropped, replaced,
+        renamed or copied between financial years.
+        """
+        required = "tally_company_mapping"
+        current_path = Path(current_path)
+
+        current_tables = {
+            str(row[0])
+            for row in db.execute(
+                "SELECT name FROM sqlite_master WHERE type='table'"
+            ).fetchall()
+        }
+        if required in current_tables:
+            return
+
+        filename = current_path.name
+        candidates = []
+        try:
+            pattern = f"FY*/Clients/*/*/Accounting/{filename}"
+            for candidate in self.storage_root.glob(pattern):
+                candidate = Path(candidate)
+                if candidate.resolve() == current_path.resolve():
+                    continue
+                if not candidate.is_file():
+                    continue
+                try:
+                    ref = sqlite3.connect(candidate, timeout=15)
+                    try:
+                        tables = {
+                            str(row[0])
+                            for row in ref.execute(
+                                "SELECT name FROM sqlite_master WHERE type='table'"
+                            ).fetchall()
+                        }
+                        if required not in tables:
+                            continue
+                        object_count = int(
+                            ref.execute(
+                                """
+                                SELECT COUNT(*)
+                                FROM sqlite_master
+                                WHERE type IN ('table','index','trigger')
+                                  AND name NOT LIKE 'sqlite_%'
+                                  AND sql IS NOT NULL
+                                """
+                            ).fetchone()[0]
+                        )
+                        candidates.append((object_count, candidate))
+                    finally:
+                        ref.close()
+                except Exception:
+                    continue
+        except Exception:
+            return
+
+        if not candidates:
+            return
+
+        candidates.sort(key=lambda item: item[0], reverse=True)
+        reference_path = candidates[0][1]
+
+        ref = sqlite3.connect(reference_path, timeout=30)
+        try:
+            table_rows = ref.execute(
+                """
+                SELECT name, sql
+                FROM sqlite_master
+                WHERE type='table'
+                  AND name NOT LIKE 'sqlite_%'
+                  AND sql IS NOT NULL
+                ORDER BY name
+                """
+            ).fetchall()
+
+            existing_tables = {
+                str(row[0])
+                for row in db.execute(
+                    "SELECT name FROM sqlite_master WHERE type='table'"
+                ).fetchall()
+            }
+
+            for name, sql in table_rows:
+                name = str(name)
+                if name in existing_tables:
+                    continue
+                db.execute(str(sql))
+                existing_tables.add(name)
+
+            index_rows = ref.execute(
+                """
+                SELECT name, tbl_name, sql
+                FROM sqlite_master
+                WHERE type='index'
+                  AND name NOT LIKE 'sqlite_%'
+                  AND sql IS NOT NULL
+                ORDER BY name
+                """
+            ).fetchall()
+
+            existing_indexes = {
+                str(row[0])
+                for row in db.execute(
+                    "SELECT name FROM sqlite_master WHERE type='index'"
+                ).fetchall()
+            }
+            for name, table_name, sql in index_rows:
+                name = str(name)
+                table_name = str(table_name)
+                if name in existing_indexes or table_name not in existing_tables:
+                    continue
+                db.execute(str(sql))
+                existing_indexes.add(name)
+
+            trigger_rows = ref.execute(
+                """
+                SELECT name, tbl_name, sql
+                FROM sqlite_master
+                WHERE type='trigger'
+                  AND name NOT LIKE 'sqlite_%'
+                  AND sql IS NOT NULL
+                ORDER BY name
+                """
+            ).fetchall()
+
+            existing_triggers = {
+                str(row[0])
+                for row in db.execute(
+                    "SELECT name FROM sqlite_master WHERE type='trigger'"
+                ).fetchall()
+            }
+            for name, table_name, sql in trigger_rows:
+                name = str(name)
+                table_name = str(table_name)
+                if name in existing_triggers or table_name not in existing_tables:
+                    continue
+                db.execute(str(sql))
+                existing_triggers.add(name)
+
+            db.commit()
+
+            final_tables = {
+                str(row[0])
+                for row in db.execute(
+                    "SELECT name FROM sqlite_master WHERE type='table'"
+                ).fetchall()
+            }
+            if required not in final_tables:
+                raise RuntimeError(
+                    "Historical Accounting Mirror schema upgrade did not create "
+                    "tally_company_mapping."
+                )
+        finally:
+            ref.close()
+
     def connect(self, client_id: int):
         if self._bound_relative_dir(client_id) is None:
             raise RuntimeError(
@@ -237,6 +403,7 @@ class LocalAccountingStore:
         path.parent.mkdir(parents=True, exist_ok=True)
         db = sqlite3.connect(path, timeout=60)
         db.row_factory = sqlite3.Row
+        self._ensure_historical_schema_compatibility(client_id, db, path)
         db.execute("PRAGMA foreign_keys=ON")
         db.execute("PRAGMA journal_mode=WAL")
         db.execute("PRAGMA synchronous=NORMAL")