For all you "supposed Devs"

here are the instructions :-
1. Using XCode, login into your Developer Account and create a provisioning profile (this will generate certificates as well) ...
2. Download the iOS Distribution certificate and the profile from dev portal
3. Double click the certificate to install it into Keychain
Download the beta ipa :
https://www.dropbox.com/s/f6tooyh15td82uc/WhatsApp-beta.ipa
Steps to resign :-
1. unzip WhatsApp-beta.ipa
2. rm -r "Payload/Application.app/_CodeSignature" "Payload/Application.app/CodeResources" 2> /dev/null | true
3. cp "YOURFILE.mobileprovision" "Payload/Application.app/embedded.mobileprovision"
4. codesign -f -s "iPhone Distribution: Certificate Name" --resource-rules "Payload/Application.app/ResourceRules.plist" "Payload/WhatsApp.app"
5. zip -qr "WhatsApp-resigned.ipa" Payload
In #3 above, replace YOURFILE.mobileprovision with the yours which you downloaded
In #4 above, replace the Certificate Name with yours as shown in Keychain
Connect your iPhone to computer. Open Organizer in XCode from 'Window' menu. Select the phone and click "Use for development" .. this will copy over the provisioning profile to the phone.
Under same phone selection, select Applications and click + at bottom. Select the resigned ipa file and let it copy over.
Note that you should have production Whatsapp already installed and working so that the beta upgrades it. Otherwise you will not get working notifications.
Hope this helps!