The changes will mean that communications with businesses by WhatsApp users — whether by email, phone or WhatsApp itself — will be visible to the application.
That information may then be used for marketing purposes, including advertising on Facebook, an earlier FAQ says.
The changes were initially expected to take effect in January itself. But a backlash from users, many of whom then switched to Signal and Telegram, led to a delay in implementation announced in the third week of January.
In the new FAQ, WhatApp says: "To give you enough time to review changes at your own pace and convenience, we’ve extended the effective date to 15 May.
"If you haven’t accepted by then, WhatsApp will not delete your account. However, you won't have full functionality of WhatsApp until you accept.
"For a short time, you'll be able to receive calls and notifications, but won't be able to read or send messages from the app."
The company did not define what "a short time" was. Neither did it say what would happen after this "short time".
It offered the following options for users:
"You can still accept the updates after 15 May. Our policy related to inactive users will apply."
The policy for inactive users is that accounts are deleted after 120 days of inactivity, with inactivity being defined as the user not connecting to WhatsApp.
"Before 15 May, you can export your chat history on Android or iPhone, and download a report of your account," the latest FAQ continued.
"If you’d like to delete your account on Android, iPhone, or KaiOS, we hope you reconsider. It is something we cannot reverse as it erases your message history, removes you from all of your WhatsApp groups, and deletes your WhatsApp back-ups."