WhatsApp is working on updates for more improvements like security, privacy and friendly user interface as per that WhatsApp has submitted a new update through Google Play Beta program and bringing up the version to v2.18.301 for Android beta users, this update is under testing and it will available to normal users in future.
This update has a feature of PIP mode & Swipe to reply option, these both feature are initiated early at the beta version 2.18.234 but for development purpose WhatsApp still not rolls out these for normal users, for beta users update your version to 2.18.301 to experience this feature.
If these feature not enable, try uninstall & again install the WhatsApp messenger application, because each time you’ll installing a WhatsApp new updated configurations are loaded. Now let see how the feature works.
Swipe to Reply
Earlier in WhatsApp you can reply to user during chatting by just holding the chat and start typing in text editor, it automatically attaches the chat for reply, or you can hold the chat and press the (i) button in the top to reply the chat user.
Now with the update of Swipe to reply feature it allows to reply a message using gesture, these same feature is implemented years ago in WhatsApp for iOS. Just swipe a message you want to reply, using gesture option feature WhatsApp automatically loads the reply message in context to your save extra time.
See the video reference of updated Swipe to Reply WhatsApp Feature,
Picture-In-Picture (PIP) Mode
Picture-In-Picture feature is initially developed at beta version 2.18.234, now this feature gets rolls out for beta version 2.18.301 this feature stream the video content of YouTube, Facebook, Instagram and other streaming videos within WhatsApp application.
When you receive or send any video link to user, you can now experience the PIP mode, also you can chat with user while playing the video within WhatsApp, but when you move on to another chat video will stopped, but in iOS it will play when moved to other chat user also, WhatsApp working on these to develop and soon normal users also get these feature in future.
See the video reference of updated PIP WhatsApp Feature,