The only selection within Viewer Builder on the Social Media dropdown settings (when I try to build a v21 release of an app) is Facebook.
I thought Twitter/Email/Copy Link might have been just baked into v21 apps - but when I launched the dev build of the app, I still only have Facebook in the social media dropdown.
If I try to build or edit a v20 release - I do still see all four social media choices in Viewer Builder.
What changed with v21 apps?
North America
Europe, Middle East and Africa
Asia Pacific