Google announced a bunch of new features for Google Allo yesterday which include incognito mode for groups, link previews, and a backup/restore function for chats. The update is yet to be pushed out to the Play Store, but you can already download Google Allo 10.0.037_RC13 apk with all these features.
Hit the links below to download the apk. To decide which one you want, you would need to know the dpi for your device. You can use the Droid Hardware Info app to find that out. Once you know the dpi for your device pick the apk with an higher dpi than yours if available. If not you will be fine with the lower dpi apk as well.
Download Google Allo 10.0.037_RC13 Apk