The Google+ Android app jumped to a new version last week, and shortly after, its Play Store page updated with a change log topped by one problematic item:
Here's the thing, moderators couldn't yet. We hit up the app, searched the site, and even asked around. The feature simply wasn't live. Now it is. Moderators can pin posts to the top of a community stream regardless of if they're using the app or the website.
You can see the feature used within the app below.
Note the green thumbtack icon.
Here's how a pinned post looks on the website.
Voila! There's no update to wait around for here, so enjoy pinning those posts.