diff --git a/htdocs/langs/en_US/admin.lang b/htdocs/langs/en_US/admin.lang
index cffd3532c05..fd86b2e7788 100644
--- a/htdocs/langs/en_US/admin.lang
+++ b/htdocs/langs/en_US/admin.lang
@@ -1421,6 +1421,8 @@ WatermarkOnDraftInvoices=Watermark on draft invoices (none if empty)
 PaymentsNumberingModule=Payments numbering model
 SuppliersPayment=Vendor payments
 SupplierPaymentSetup=Vendor payments setup
+InvoiceCheckPosteriorDate=Check facture date before validation
+InvoiceCheckPosteriorDateHelp=Validating an invoice will be forbidden if its date is anterior to the date of last invoice of same type.
 ##### Proposals #####
 PropalSetup=Commercial proposals module setup
 ProposalsNumberingModules=Commercial proposal numbering models
diff --git a/htdocs/langs/en_US/bills.lang b/htdocs/langs/en_US/bills.lang
index 851323cadd9..993f5a21b2b 100644
--- a/htdocs/langs/en_US/bills.lang
+++ b/htdocs/langs/en_US/bills.lang
@@ -156,6 +156,7 @@ ErrorInvoiceAvoirMustBeNegative=Error, correct invoice must have a negative amou
 ErrorInvoiceOfThisTypeMustBePositive=Error, this type of invoice must have an amount excluding tax positive (or null)
 ErrorCantCancelIfReplacementInvoiceNotValidated=Error, can't cancel an invoice that has been replaced by another invoice that is still in draft status
 ErrorThisPartOrAnotherIsAlreadyUsedSoDiscountSerieCantBeRemoved=This part or another is already used so discount series cannot be removed.
+ErrorInvoiceIsNotLastOfSameType=Error: The date of invoice %s  is %s. It must be posterior or equal to last date for same type invoices (%s). Please change the invoice date.
 BillFrom=From
 BillTo=To
 ActionsOnBill=Actions on invoice