[Push API] Web push subscription age affects delivery rates

Hello!

I think that this study that I have published needs your attention:
https://blog.pushpad.xyz/2018/09/web-push-subscription-age-affects-delivery-rates/

Your opinion would be greatly appreciated.
Also, are you aware of any strategies that are being implemented in
browsers or push services (e.g. FCM, Autopush) in order to mark inactive
subscriptions as expired?


Thanks
Marco Colli