WhatsApp is working on the technology to independently encrypt your backups in the cloud, and says that in the most recent beta update on Android (18.104.22.168), the system has been enabled. WhatsApp has always maintained that the messages that are going through are end-to-end encrypted, which basically means that predators will not be able to see them as easily, but, if the same backup is stored in the cloud, authorities can make use of a search warrant to search the data, with the two cloud services being Google Drive and iCloud.
How it Works
If you opt to keep your chat history and media backed up for security, there is one major caveat, which occurs if the user forgets the 64-digit recovery code or passcode, as they might be locked away from the same for a permanent time frame with not even WhatsApp being able to help. So, if you are fine with this risk, then you can enter the beta test group or wait for a proper stable build, to check out this new feature. If you are part of the beta, you need to check your version as there are reports suggesting that this feature is expanding rapidly. You cannot call or message someone from the companion device if the user is on an old version of the application.