Alerts mailing list
The Bitcoin Protocol specification previously supported the broadcast of Alerts. In the past, an unofficial email relay was provided that rebroadcast these block chain related alerts. To subscribe via email, you sent an email to email@example.com  to receive an email asking you to verify your subscription.
Alternatively, you can browse to the Google Group for the list .
Verify alerts and obtain the latest status information
When you received an alert, you should have immediately verified it was official by running "bitcoin-cli getinfo" (but see notes below), gone to bitcoin.org  to obtain more details and background, or joined the #bitcoin IRC channels on Freenode to obtain the latest information.
- Alerts were broadcast to a specified range of Bitcoin versions.
- The email relay used a specially patched version of bitcoind that should have reported and therefore relayed any alert broadcast for any version.
- You therefore had to verify whether or not the alert was actually relevant to your particular version of Bitcoin Core.
- Alerts were also independent of blocks or transactions and had a defined time-to-live.
- The email relay polled bitcoind every six minutes.
The now-discontinued service was operated by Gary Mulder .