Marco wants a better email client for his iPhone. He's not a fan of HTML based email. Leo says it's dangerous, but most mail clients including Apple Mail panders to users who want to see pretty pictures. But it's just not as secure. They do prevent loading of images unless you request them, but plain text will always be more secure.
How about a good antivirus for his iPhone? Leo says he doesn't have to worry about viruses in an iPhone or macOS. There haven't been any successful malware attempts on iOS.