The first in English is called disappearing mode and consists in the self destruction of a chat with a timer. In particular, after a number of seconds after reading a message from the interlocutor, the message will disappear automatically. The second function, really very requested concerns the possibility to move all chats from iPhone to Android (and presumably the opposite.)
On iphone will appear “Move chats to Android” and will allow to transfer not only conversations but also all media files. Besides being able to transfer chats from one operating system to another, you can also transfer them to a different phone number. Each registration to whatsapp happens by phone number which turns out to be also our “login” in the application.
It follows that if we change phone number, the new number will represent a new registration and then it will leave completely devoid of conversations. Whatsapp is also working on multiplatform support that will allow it to work simultaneously on multiple arrangements, such as telegram. At the moment you can install whatsapp only on your iphone but if we have two iphones or a secondary android, we will not be able to use the app outside the main device.
With multi-platform support things will change: you can manage whatsapp while opening it on multiple devices both with the same operating system and with different os.