I'm trying to find a way with an iRule (or any functionality really) to take a url like https://apple.fruit.com/application/xyz.html and convert it to https://peanut.bean.com/application...
What updates are you referring to? The features to rewrite the URI and user agent can be done as described in the blog post. The User-Agent can be modified with the "HTTP::header replace" command.
If you can be more specific about what issues you need to be addressed, we'll see if we can help.