Just upgraded my iPhone 4 to Nexus 4, and could not find on Google a reasonable answer to this question. Is there any good app that does this? Or, what should be the process?
there is no simple way of doing so, you have to do a lot of technical mumble-jumble for this.
Caution :: Do not install whatsapp on your android device beforehand.
if you are ready then:
[I have not tried this with MAC, this works fine in PC(Win) and Linux]
I made the switch from iPhone 5s to Nexus 6 three days ago. I transferred WhatsApp conversations including attachments from my old iPhone to new Nexus 6 with the help of BackupTrans, the desktop utility mentioned in this article http://www.easyphonerecovery.com/transfer-whatsapp-chat-history-messages-iphone-to-android.html Here are the steps to transfer WhatsApp messages from iPhone to Android with this software:
1) Launch the program on your Windows PC or Mac and then connect both your Android device and iPhone to your computer via USB cable.
2) Click 'Back up my data' when a message pops out on your Android phone’s screen. Now the software will read WhatsApp messages from your Android and iPhone and show them on its main interface.
3) Finally go to the top tool and click "Transfer Messages from iPhone to Android" button.
Note: You will need enable USB debugging before connecting your Android phone to this program and also make sure you have iTunes 11 or above installed on your computer.
It's a paid program but I couldn't find any other software or app that can migrate WhatsApp chat history from iPhone to Android. There are some apps on Play Store but none of them worked for me. I know it's an old question but I'm sure my answer will others who are looking to transfer WhatsApp chats from iPhone to their Android device.