A few weeks ago, a WhatsApp beta build revealed work on disappearing messages that vanish after they’re read. Now, WhatsApp is developing another ephemeral messaging feature. Here are the details. View-once text messages underway Last month, WABetaInfo reported that a WhatsApp beta build on TestFlight had added an “After reading” option to the app’s existing disappearing messages feature. Currently, WhatsApp’s disappearing messages setting officially supports timers for 24 hours, 7 days, and 90 days. With the new option, which has yet to roll out broadly, users will also be able to set new messages to vanish after they’ve been read. Now, WABetaInfo reports that WhatsApp is working on yet another ephemeral messaging feature. Although it isn’t available to beta testers yet, the feature will let users send view-once text messages, expanding an option that is already available for photos, videos, and voice notes.…