In the feature list it says that Phoenix has Autocomplete. Where is it at?
‘Autocomplete’ has been implemented in the Mail Options dialog. If you type an e-mail address in the To/CC/BCC field Phoenix should suggest the e-mail address. If not, maybe your Favourites list is empty? For your information, the Autocomplete works in conjunction with the Favourites list (with up to a maximum of 20 entries). If you press the enter key after an e-mail address it will be automatically included to the Favourites list. Deleting an entry is simple too: just hold the CTRL key and click on the entry.