HealthUnlocked have advised of an upcoming change of the Posts tab per the above image incorporating visual and functional changes to the site.
Here's a copy of the message from HealthUnlocked:
We hope you are having a really nice start of the year.
Today, we want to share with all of you some exciting news! You will soon be able to see on your communities an updated layout of the posts tab, which also includes bigger changes “behind-the-scenes” (technical side) that will hopefully make your experience of the page even better.
The new layout better highlights how you can filter posts by latest, unanswered, popular, pinned by admins and recently active (those posts with the most recent contributions whether it is a new reply or the post itself has been just created).
You will also have at your right hand side the option to search posts on your community *** and see the archive section, which groups all posts submitted to the community by year and month.
*** Note that the Health Unlocked Search function to the left of the avartar currently doesn't return locked posts, but the Post page search does!