How to turn off comment notifications

To unsubscribe from comment notifications on dropbox.com:

1. Log in to dropbox.com.
2. Click the name of the file you want to disable comments on.
3. Click "…" (ellipsis) at the bottom right of the preview. 
4. Click Unsubscribe.

To unsubscribe from comment notification in the mobile app:

1. Open the Dropbox app. 
2. Tap the file you want to disable comments on. 
3. Tap the textbox that says Type a comment. 
4. In the upper left-hand corner, tap the bell icon. If it’s blue, that means you’re subscribed to notifications.