Sort Order Is Sticky on Mobile
You can set a default sort order for a community feed. Users can select some other sort order that stays in place when they navigate away from a feed and then return. You get a great way to design your users’ initial experience, and users get greater control over how they view their feeds.
Where: This change applies to Lightning communities accessed through Lightning Experience and Salesforce Classic in Essentials, Enterprise, Performance, Unlimited, and Developer editions.