diff --git a/Purchases/Misc/RCCrossPlatformSupport.h b/Purchases/Misc/RCCrossPlatformSupport.h
index 89482cc062..9669c94e83 100644
--- a/Purchases/Misc/RCCrossPlatformSupport.h
+++ b/Purchases/Misc/RCCrossPlatformSupport.h
@@ -46,6 +46,15 @@
 #define UI_DEVICE_AVAILABLE 0
 #endif
 
+// Should match available platforms in
+// https://developer.apple.com/documentation/watchkit/wkinterfacedevice?language=objc
+#if TARGET_OS_WATCH
+#define WKINTERFACE_DEVICE_AVAILABLE 1
+#else
+#define WKINTERFACE_DEVICE_AVAILABLE 0
+#endif
+
+
 // Should match available platforms in
 // https://developer.apple.com/documentation/iad/adclient?language=objc
 #if TARGET_OS_IOS
diff --git a/Purchases/Misc/RCSystemInfo.h b/Purchases/Misc/RCSystemInfo.h
index f34d40fd28..d7774c98c6 100644
--- a/Purchases/Misc/RCSystemInfo.h
+++ b/Purchases/Misc/RCSystemInfo.h
@@ -26,7 +26,9 @@ NS_ASSUME_NONNULL_BEGIN
 + (NSString *)frameworkVersion;
 + (NSString *)systemVersion;
 + (NSString *)appVersion;
++ (NSString *)buildVersion;
 + (NSString *)platformHeader;
++ (nullable NSString *)identifierForVendor;
 
 + (NSURL *)serverHostURL;
 + (nullable NSURL *)proxyURL;
diff --git a/Purchases/Misc/RCSystemInfo.m b/Purchases/Misc/RCSystemInfo.m
index c4348227a3..8a658baeea 100644
--- a/Purchases/Misc/RCSystemInfo.m
+++ b/Purchases/Misc/RCSystemInfo.m
@@ -62,10 +62,24 @@ + (NSString *)appVersion {
     return version ?: @"";
 }
 
++ (NSString *)buildVersion {
+    NSString *version = NSBundle.mainBundle.infoDictionary[@"CFBundleVersion"];
+    return version ?: @"";
+}
+
 + (NSString *)platformHeader {
     return self.forceUniversalAppStore ? @"iOS" : PLATFORM_HEADER;
 }
 
++ (nullable NSString *)identifierForVendor {
+#if UI_DEVICE_AVAILABLE
+    return UIDevice.currentDevice.identifierForVendor.UUIDString;
+#elif WKINTERFACE_DEVICE_AVAILABLE
+    return WKInterfaceDevice.currentDevice.identifierForVendor.UUIDString;
+#endif
+    return nil;
+}
+
 + (NSURL *)defaultServerHostURL {
     return [NSURL URLWithString:defaultServerHostName];
 }
diff --git a/Purchases/Networking/RCHTTPClient.m b/Purchases/Networking/RCHTTPClient.m
index e703398f5a..63a8b12eca 100644
--- a/Purchases/Networking/RCHTTPClient.m
+++ b/Purchases/Networking/RCHTTPClient.m
@@ -201,6 +201,7 @@ - (NSDictionary *)defaultHeaders {
         @"X-Platform-Version": RCSystemInfo.systemVersion,
         @"X-Platform-Flavor": self.systemInfo.platformFlavor,
         @"X-Client-Version": RCSystemInfo.appVersion,
+        @"X-Client-Build-Version": RCSystemInfo.buildVersion,
         @"X-Observer-Mode-Enabled": observerMode
     }];
 
@@ -209,6 +210,11 @@ - (NSDictionary *)defaultHeaders {
         headers[@"X-Platform-Flavor-Version"] = platformFlavorVersion;
     }
 
+    NSString * _Nullable idfv = RCSystemInfo.identifierForVendor;
+    if (idfv) {
+        headers[@"X-Apple-Device-Identifier"] = idfv;
+    }
+
     return headers;
 }
 
diff --git a/PurchasesTests/Networking/HTTPClientTests.swift b/PurchasesTests/Networking/HTTPClientTests.swift
index d47efb3ba9..5f17cf9429 100644
--- a/PurchasesTests/Networking/HTTPClientTests.swift
+++ b/PurchasesTests/Networking/HTTPClientTests.swift
@@ -319,6 +319,40 @@ class HTTPClientTests: XCTestCase {
         expect(headerPresent).toEventually(equal(true))
     }
 
+    func testAlwaysPassesClientBuildVersion() {
+        let path = "/a_random_path"
+        var headerPresent = false
+
+        let version = Bundle.main.infoDictionary!["CFBundleVersion"] as! String
+
+        stub(condition: hasHeaderNamed("X-Client-Build-Version", value: version )) { request in
+            headerPresent = true
+            return HTTPStubsResponse(data: Data.init(), statusCode:200, headers:nil)
+        }
+
+        self.client.performRequest("POST", serially: true, path: path, body: Dictionary.init(),
+                                   headers: ["test_header": "value"], completionHandler:nil)
+
+        expect(headerPresent).toEventually(equal(true))
+    }
+
+    func testAlwaysPassesAppleDeviceIdentifier() {
+        let path = "/a_random_path"
+        var headerPresent = false
+
+        let idfv = UIDevice.current.identifierForVendor!.uuidString
+
+        stub(condition: hasHeaderNamed("X-Apple-Device-Identifier", value: idfv )) { request in
+            headerPresent = true
+            return HTTPStubsResponse(data: Data.init(), statusCode:200, headers:nil)
+        }
+
+        self.client.performRequest("POST", serially: true, path: path, body: Dictionary.init(),
+                                   headers: ["test_header": "value"], completionHandler:nil)
+
+        expect(headerPresent).toEventually(equal(true))
+    }
+
     func testDefaultsPlatformFlavorToNative() {
         let path = "/a_random_path"
         var headerPresent = false