1) Live notifications via email/text
2) D2JSP app
3) Discord channel
4) Live dynamic timer countdown

There is a discord: https://forums.d2jsp.org/topic.php?t=82647839&f=272

I'm not sure what you mean by #4, but I believe #1 and #2 go together and have been suggested before https://forums.d2jsp.org/topic.php?t=73932248&f=120

Don't think there's any plans on an app at this time

Btw make sure to use a poll when posting a suggestion so people can vote
https://forums.d2jsp.org/topic.php?t=57896631&f=258

Okay cool.

For point #4, I was referring to the time that displays until a next bump/reply/etc

So have the timer actually counting down. I think this would be better. I often refresh the page to update timer and that means more network requests to server