diff --git a/erpnext/stock/stock_ledger.py b/erpnext/stock/stock_ledger.py
index a781479..7e5c231 100644
--- a/erpnext/stock/stock_ledger.py
+++ b/erpnext/stock/stock_ledger.py
@@ -8,9 +8,8 @@
 import frappe
 from frappe import _
 from frappe.model.meta import get_field_precision
-from frappe.query_builder.functions import Sum
+from frappe.query_builder.functions import CombineDatetime, Sum
 from frappe.utils import cint, cstr, flt, get_link_to_form, getdate, now, nowdate
-from pypika import CustomFunction
 
 import erpnext
 from erpnext.stock.doctype.bin.bin import update_qty as update_bin_qty
@@ -1158,16 +1157,15 @@
 	item_code, warehouse, batch_no, posting_date, posting_time, creation=None
 ):
 
-	Timestamp = CustomFunction("timestamp", ["date", "time"])
-
 	sle = frappe.qb.DocType("Stock Ledger Entry")
 
-	timestamp_condition = Timestamp(sle.posting_date, sle.posting_time) < Timestamp(
+	timestamp_condition = CombineDatetime(sle.posting_date, sle.posting_time) < CombineDatetime(
 		posting_date, posting_time
 	)
 	if creation:
 		timestamp_condition |= (
-			Timestamp(sle.posting_date, sle.posting_time) == Timestamp(posting_date, posting_time)
+			CombineDatetime(sle.posting_date, sle.posting_time)
+			== CombineDatetime(posting_date, posting_time)
 		) & (sle.creation < creation)
 
 	batch_details = (
diff --git a/erpnext/stock/utils.py b/erpnext/stock/utils.py
index d40218e..2120304 100644
--- a/erpnext/stock/utils.py
+++ b/erpnext/stock/utils.py
@@ -7,6 +7,7 @@
 
 import frappe
 from frappe import _
+from frappe.query_builder.functions import CombineDatetime
 from frappe.utils import cstr, flt, get_link_to_form, nowdate, nowtime
 
 import erpnext
@@ -143,12 +144,10 @@
 
 
 def get_serial_nos_data_after_transactions(args):
-	from pypika import CustomFunction
 
 	serial_nos = set()
 	args = frappe._dict(args)
 	sle = frappe.qb.DocType("Stock Ledger Entry")
-	Timestamp = CustomFunction("timestamp", ["date", "time"])
 
 	stock_ledger_entries = (
 		frappe.qb.from_(sle)
@@ -157,7 +156,8 @@
 			(sle.item_code == args.item_code)
 			& (sle.warehouse == args.warehouse)
 			& (
-				Timestamp(sle.posting_date, sle.posting_time) < Timestamp(args.posting_date, args.posting_time)
+				CombineDatetime(sle.posting_date, sle.posting_time)
+				< CombineDatetime(args.posting_date, args.posting_time)
 			)
 			& (sle.is_cancelled == 0)
 		)