How to transfer WhatsApp conversations to a new phone?

I recently changed smartphones from an unknown to Samsung, and I've lost my WhatsApp conversations. I want them on the new phone. I have reinstalled it on the new phone, and the msgstore.db.crypt files are there, but WhatsApp does not read the older conversations back. What I would like to do is have WhatsApp appear as an unbroken list of chats so that the date that I changed phones is not apparent in the list of chats.