The ActivitySmith app icon is the one you look at every time a push notification lands on your lock screen. It should feel like yours.
You can now pick from 36 custom app icons - no ActivitySmith branding. Tap Settings → App Icon inside the app and choose the one that fits.
200, 2xx, 404, 503, and more.CORE, FEED, SYNC, LINK, and others.There's a known iOS bug where push notifications can still render the default icon on the lock screen even after you switch. Apple has acknowledged it and a fix is pending.
Until then, the workaround is simple:
New push notifications will then show your chosen icon on the lock screen.
Available in the ActivitySmith iOS app version 1.6.0 and newer.