WhatsApp is going to make it easier to add and synchronize contacts in the app, switching to in-app storage for such info, ensuring that a user can restore their WhatsApp contacts even if they switch devices, and it is also going to use a new encryption solution to simplify contact sharing.

First, WhatsApp enables saving your contacts within the application and their management through the desktop version of the application, besides its mobile interface.
WhatsApp self declares that:

"Until now, contacts could only be added from your mobile device, either by manually typing in a phone number or scanning a QR code. Very soon we will have the ability to add and manage contacts directly from the comfort of your keyboard on WhatsApp Web and Windows— and eventually other linked devices."

This will give you more ways to manage your WhatsApp connections, and use the application for managing and maintaining your contacts.

In short, this means that if you lose your phone or change your phone number, you would still have a possibility to restore your WhatsApp contacts from the cloud storage.

But the ability to manage contacts on a desktop, too, will make it an even more valuable element for business users who can use their contacts in larger operations.

Though storing your information in the cloud also brings along some privacy trade-offs, and in this element WhatsApp has also developed a much more advanced encryption system to store and share relevant data.
The process, dubbed "Identity Proof Linked Storage" or IPLS, will be enabled for WhatsApp users to save contacts and auto-restore directly through WhatsApp.

In other words, "with IPLS, you will be able to create contacts directly in WhatsApp and, at your discretion, either sync them to your phone or save them securely only to WhatsApp, giving you the ability to create contacts that are specific to your account. If you use linked devices, this also allows you to add and manage contacts seamlessly regardless of which device you're on."

The third feature is that now users can also save a contact straight to WhatsApp.

"These WhatsApp contacts are convenient if you share your phone with others or if you have business and personal contacts, that you might want to keep separate, in case you manage multiple WhatsApp accounts on your phone. Contacts saved in WhatsApp will automatically be recovered in case you lose your phone or change devices."

The expanded view is that users will eventually be able to manage and save contacts by usernames only, which enables extra privacy in that you won't have to share your phone number before messaging somebody.

Thus, more ways of managing your WhatsApp connections while keeping the privacy and security across devices.

These are significant security improvements for WhatsApp, in terms of limiting both the access to and exposure of your data. But while these details won't matter to all users, having the capability to store your contacts completely independently of your device could be a highly useful add-on for many applications.