If this was added, I think it should be only an option and should be disabled by default. It seems decent as a "supporter feature" since lacking it won't have a huge negative impact to anyone. Nor would I say implementing this (if approved) should be a high priority. But I'd probably use it if available.
@JoeyKicks
This feature might cause scanlator groups to compete to pump out poor quality speed scanlations.
Well that sorta happens now. That might become worse if the feature cut off notifications to the current chapter rather than just old chapters.
Say the latest updated chapter was 100. Another group does chapter 90, and you don't get a notification (if the feature is on). Another group does chapter 100 (perhaps with better quality), you do get a notification.
Maybe instead of just the most recent chapter being immune, it could ignore this for the most recent 5-10 chapters. That basically covers most bulk releases. Or maybe instead of how many chapters, it considers the dates.
Also if someone does little bonus chapters, you might not want it to cover those (or you might miss them). Aka you are at chapter 100 but someone did the 85.5 Halloween special timed to release on Halloween instead of sequentially. I'd want a notification for that still. So even though it isn't the most recent chapter, it could look and see 85.5 was not previously uploaded (whether later deleted or not), so the notification is shown.