@@ -0,0 +1,4 @@
+Significance: patch
+Type: fix
+
+Accept legacy four-digit Argentine postcodes in the Checkout block again.
@@ -258,7 +258,7 @@
 		"fast-deep-equal": "^3.1.3",
 		"fast-sort": "^3.4.0",
 		"html-react-parser": "3.0.4",
-		"postcode-validator": "3.10.22",
+		"postcode-validator": "3.9.2",
 		"preact": "^10.24.2",
 		"prop-types": "^15.8.1",
 		"react-number-format": "5.4.5",
 
@@ -197,6 +197,17 @@ describe( 'isPostcode', () => {
 		[ true, '2000', 'AU' ],
 		[ false, '2000#', 'AU' ],
 
+		// Argentina uses the fallback too. The legacy four digit codes are
+		// still in everyday use next to the lettered format; postcode-validator
+		// 3.10 started rejecting them.
+		[ true, '1213', 'AR' ],
+		[ true, '7540', 'AR' ],
+		[ true, 'C1213', 'AR' ],
+		[ true, 'C1213ABC', 'AR' ],
+		[ true, 'B7540', 'AR' ],
+		[ false, '142', 'AR' ],
+		[ false, 'I1213', 'AR' ],
+
 		// Unknown country codes — assumed valid since no regex applies.
 		[ true, '12345', 'XX' ],
 		[ true, 'anything', 'ZZ' ],
 
@@ -1,7 +1,7 @@
 {
 	"generatedFrom": {
 		"package": "postcode-validator",
-		"version": "3.10.22"
+		"version": "3.9.2"
 	},
 	"rules": {
 		"AT": {
Original file line number	Diff line number	Diff line change
`@@ -1,7 +1,7 @@`
`1`	`1`	`{`
`2`	`2`	`"generatedFrom": {`
`3`	`3`	`"package": "postcode-validator",`
`4`		`- "version": "3.10.22"`
	`4`	`+ "version": "3.9.2"`
`5`	`5`	`},`
`6`	`6`	`"rules": {`
`7`	`7`	`"AT": {`