README.md in lockbox-0.3.5 vs README.md in lockbox-0.3.6

@@ -778,10 +778,24 @@
 end
 ```
 
 ## Upgrading
 
+### 0.3.6
+
+0.3.6 makes content type detection more reliable for Active Storage. You can check and update the content type of existing files with:
+
+```ruby
+User.find_each do |user|
+  license = user.license
+  content_type = Marcel::MimeType.for(license.download, name: license.filename.to_s)
+  if content_type != license.content_type
+    license.update!(content_type: content_type)
+  end
+end
+```
+
 ### 0.2.0
 
 0.2.0 brings a number of improvements. Here are a few to be aware of:
 
 - Added `encrypts` method for database fields
@@ -835,10 +849,10 @@
 - [Report bugs](https://github.com/ankane/lockbox/issues)
 - Fix bugs and [submit pull requests](https://github.com/ankane/lockbox/pulls)
 - Write, clarify, or fix documentation
 - Suggest or add new features
 
-To get started with development and testing:
+To get started with development, [install Libsodium](https://github.com/crypto-rb/rbnacl/wiki/Installing-libsodium) and run:
 
 ```sh
 git clone https://github.com/ankane/lockbox.git
 cd lockbox
 bundle install