Added upgrade guide

_data/menu.yml

@@ -3,6 +3,7 @@ Getting Started:
     Terminology: '/terminology/'
     Requirements: '/requirements/'
     Installation: '/installation/'
+    Upgrade Guide: '/upgrade-guide/'
     Database Setup: '/database-setup/'
     Framework Integrations: '/framework-integrations/'
     V5 Security Improvements: '/v5-security-improvements/'

installation.md

@@ -54,7 +54,7 @@ The public key should be distributed to any services (for example resource serve
 
 ## Generating encryption keys
 
-To generate an encryption key for the `AuthorizationServer` run the following code:
+To generate an encryption key for the `AuthorizationServer` run the following command in the terminal:
 
 {% highlight shell %}
 php -r 'echo base64_encode(random_bytes(32)), PHP_EOL;'

upgrade-guide.md

@@ -0,0 +1,30 @@
+---
+layout: default
+title: Upgrade Guide
+permalink: /upgrade-guide/
+---
+
+# Upgrade Guide
+
+## 5.1.x → 6.0.x
+
+Version `6.0.0` is not backwards compatible with version `5.1.x` but only requires you to make one like of code change:
+
+```patch
+  $server = new AuthorizationServer(
+      $clientRepository,
+      $accessTokenRepository,
+      $scopeRepository,
+      $privateKeyPath,
++     'lxZFUEsBCJ2Yb14IF2ygAHI5N4+ZAUXXaSeeJm6+twsUmIen'
+-      $publicKeyPath
+  );
+```
+
+All you need to do is replace the public key that was being passed into the constructor of `AuthorizationServer` with a 32 bit encryption key.
+
+To generate an encryption key for the `AuthorizationServer` run the following command in the terminal:
+
+{% highlight shell %}
+php -r 'echo base64_encode(random_bytes(32)), PHP_EOL;'
+{% endhighlight %}