Update UPGRADE.md (#27)

UPGRADE.md

@@ -3,19 +3,19 @@ How to upgrade?
 If you want to upgrade you sdk to the lastest, please check the following points:
 
 ## Version
-The latest version is `v5.0.3`, you can upgrade sdk by [CocoaPods](https://cocoapods.org/) and [Carthage](https://github.com/Carthage/Carthage).
+The latest version is `v5.0.4`, you can upgrade sdk by [CocoaPods](https://cocoapods.org/) and [Carthage](https://github.com/Carthage/Carthage).
 
 For example:
 
-if you use [CocoaPods](https://cocoapods.org/), please make sure you pod repo contains `v5.0.3`, you can use `pod search AffirmSDK` to check it. Otherwise, you should update pod repo before upgrade.
+if you use [CocoaPods](https://cocoapods.org/), please make sure you pod repo contains `v5.0.4`, you can use `pod search AffirmSDK` to check it. Otherwise, you should update pod repo before upgrade.
 
 
 ## Fetch updated library
 
 If you already use specific sdk version in Podfile, please modify the line related to affirmSDK as follows:
 
 ```
-pod 'AffirmSDK', '~> 5.0.3'
+pod 'AffirmSDK', '~> 5.0.4'
 ```
 
 Otherwise, just use `pod update AffirmSDK` in terminal to update AffirmSDK.