diff --git a/CoreFoundation/Locale.subproj/CFCalendar.c b/CoreFoundation/Locale.subproj/CFCalendar.c
index 6e68bd270a..ce5196dc2e 100644
--- a/CoreFoundation/Locale.subproj/CFCalendar.c
+++ b/CoreFoundation/Locale.subproj/CFCalendar.c
@@ -236,14 +236,23 @@ CFCalendarRef CFCalendarCopyCurrent(void) {
 }
 
 Boolean _CFCalendarInitWithIdentifier(CFCalendarRef calendar, CFStringRef identifier) {
-    if (identifier != kCFGregorianCalendar && identifier != kCFBuddhistCalendar && identifier != kCFJapaneseCalendar && identifier != kCFIslamicCalendar && identifier != kCFIslamicCivilCalendar && identifier != kCFHebrewCalendar && identifier != kCFChineseCalendar) {
+    if (identifier != kCFGregorianCalendar && identifier != kCFBuddhistCalendar && identifier != kCFJapaneseCalendar && identifier != kCFIslamicCalendar && identifier != kCFIslamicCivilCalendar && identifier != kCFHebrewCalendar && identifier != kCFRepublicOfChinaCalendar && identifier != kCFPersianCalendar && identifier != kCFCalendarIdentifierCoptic && identifier != kCFCalendarIdentifierEthiopicAmeteMihret && identifier != kCFCalendarIdentifierEthiopicAmeteAlem && identifier != kCFChineseCalendar && identifier != kCFISO8601Calendar && identifier != kCFIslamicTabularCalendar && identifier != kCFIslamicUmmAlQuraCalendar) {
         if (CFEqual(kCFGregorianCalendar, identifier)) identifier = kCFGregorianCalendar;
         else if (CFEqual(kCFBuddhistCalendar, identifier)) identifier = kCFBuddhistCalendar;
         else if (CFEqual(kCFJapaneseCalendar, identifier)) identifier = kCFJapaneseCalendar;
         else if (CFEqual(kCFIslamicCalendar, identifier)) identifier = kCFIslamicCalendar;
         else if (CFEqual(kCFIslamicCivilCalendar, identifier)) identifier = kCFIslamicCivilCalendar;
         else if (CFEqual(kCFHebrewCalendar, identifier)) identifier = kCFHebrewCalendar;
+        else if (CFEqual(kCFRepublicOfChinaCalendar, identifier)) identifier = kCFRepublicOfChinaCalendar;
+        else if (CFEqual(kCFPersianCalendar, identifier)) identifier = kCFPersianCalendar;
+        else if (CFEqual(kCFIndianCalendar, identifier)) identifier = kCFIndianCalendar;
+        else if (CFEqual(kCFCalendarIdentifierCoptic, identifier)) identifier = kCFCalendarIdentifierCoptic;
+        else if (CFEqual(kCFCalendarIdentifierEthiopicAmeteMihret, identifier)) identifier = kCFCalendarIdentifierEthiopicAmeteMihret;
+        else if (CFEqual(kCFCalendarIdentifierEthiopicAmeteAlem, identifier)) identifier = kCFCalendarIdentifierEthiopicAmeteAlem;
         else if (CFEqual(kCFChineseCalendar, identifier)) identifier = kCFChineseCalendar;
+        else if (CFEqual(kCFISO8601Calendar, identifier)) identifier = kCFISO8601Calendar;
+        else if (CFEqual(kCFIslamicTabularCalendar, identifier)) identifier = kCFIslamicTabularCalendar;
+        else if (CFEqual(kCFIslamicUmmAlQuraCalendar, identifier)) identifier = kCFIslamicUmmAlQuraCalendar;
         else return false;
     }
     
diff --git a/CoreFoundation/Locale.subproj/CFLocaleKeys.c b/CoreFoundation/Locale.subproj/CFLocaleKeys.c
index 09ae3145fd..a515818fb9 100644
--- a/CoreFoundation/Locale.subproj/CFLocaleKeys.c
+++ b/CoreFoundation/Locale.subproj/CFLocaleKeys.c
@@ -126,7 +126,7 @@ CONST_STRING_DECL(kCFCalendarIdentifierChinese, "chinese");
 CONST_STRING_DECL(kCFCalendarIdentifierRepublicOfChina, "roc");
 CONST_STRING_DECL(kCFCalendarIdentifierPersian, "persian");
 CONST_STRING_DECL(kCFCalendarIdentifierIndian, "indian");
-CONST_STRING_DECL(kCFCalendarIdentifierISO8601, "");
+CONST_STRING_DECL(kCFCalendarIdentifierISO8601, "iso8601");
 CONST_STRING_DECL(kCFCalendarIdentifierCoptic, "coptic");
 CONST_STRING_DECL(kCFCalendarIdentifierEthiopicAmeteMihret, "ethiopic");
 CONST_STRING_DECL(kCFCalendarIdentifierEthiopicAmeteAlem, "ethiopic-amete-alem");
diff --git a/Foundation/NSCalendar.swift b/Foundation/NSCalendar.swift
index 624b103408..f483d88d8d 100644
--- a/Foundation/NSCalendar.swift
+++ b/Foundation/NSCalendar.swift
@@ -53,7 +53,7 @@ extension NSCalendar {
         public static let ethiopicAmeteMihret = NSCalendar.Identifier("ethiopic")
         public static let ethiopicAmeteAlem = NSCalendar.Identifier("ethiopic-amete-alem")
         public static let hebrew = NSCalendar.Identifier("hebrew")
-        public static let ISO8601 = NSCalendar.Identifier("")
+        public static let ISO8601 = NSCalendar.Identifier("iso8601")
         public static let indian = NSCalendar.Identifier("indian")
         public static let islamic = NSCalendar.Identifier("islamic")
         public static let islamicCivil = NSCalendar.Identifier("islamic-civil")
diff --git a/TestFoundation/TestNSCalendar.swift b/TestFoundation/TestNSCalendar.swift
index 3b11faa6f9..7406e15338 100644
--- a/TestFoundation/TestNSCalendar.swift
+++ b/TestFoundation/TestNSCalendar.swift
@@ -20,9 +20,11 @@ class TestNSCalendar: XCTestCase {
     
     static var allTests: [(String, (TestNSCalendar) -> () throws -> Void)] {
         return [
+            ("test_allCalendars", test_allCalendars),
             ("test_gettingDatesOnGregorianCalendar", test_gettingDatesOnGregorianCalendar ),
             ("test_gettingDatesOnHebrewCalendar", test_gettingDatesOnHebrewCalendar ),
             ("test_gettingDatesOnChineseCalendar", test_gettingDatesOnChineseCalendar),
+            ("test_gettingDatesOnISO8601Calendar", test_gettingDatesOnISO8601Calendar),
             ("test_copy",test_copy),
             ("test_addingDates", test_addingDates)
             // Disabled because this fails on linux https://bugs.swift.org/browse/SR-320
@@ -30,6 +32,30 @@ class TestNSCalendar: XCTestCase {
         ]
     }
     
+    func test_allCalendars() {
+        for identifier in [
+            Calendar.Identifier.buddhist,
+            Calendar.Identifier.chinese,
+            Calendar.Identifier.coptic,
+            Calendar.Identifier.ethiopicAmeteAlem,
+            Calendar.Identifier.ethiopicAmeteMihret,
+            Calendar.Identifier.gregorian,
+            Calendar.Identifier.hebrew,
+            Calendar.Identifier.indian,
+            Calendar.Identifier.islamic,
+            Calendar.Identifier.islamicCivil,
+            Calendar.Identifier.islamicTabular,
+            Calendar.Identifier.islamicUmmAlQura,
+            Calendar.Identifier.iso8601,
+            Calendar.Identifier.japanese,
+            Calendar.Identifier.persian,
+            Calendar.Identifier.republicOfChina
+            ] {
+                let calendar = Calendar(identifier: identifier)
+                XCTAssertEqual(identifier,calendar.identifier)
+        }
+    }
+
     func test_gettingDatesOnGregorianCalendar() {
         let date = Date(timeIntervalSince1970: 1449332351)
         
@@ -41,6 +67,19 @@ class TestNSCalendar: XCTestCase {
         XCTAssertEqual(components.month, 12)
         XCTAssertEqual(components.day, 5)
     }
+
+    func test_gettingDatesOnISO8601Calendar() {
+        let date = Date(timeIntervalSince1970: 1449332351)
+
+        var calendar = Calendar(identifier: .iso8601)
+        calendar.timeZone = TimeZone(identifier: "UTC")!
+        let components = calendar.dateComponents([.year, .month, .day], from: date)
+
+        XCTAssertEqual(components.year, 2015)
+        XCTAssertEqual(components.month, 12)
+        XCTAssertEqual(components.day, 5)
+    }
+
     
     func test_gettingDatesOnHebrewCalendar() {
         let date = Date(timeIntervalSince1970: 1552580351)