# What changed in smtp-server

> 3 changes in smtp-server 3 from its official release notes, upgrade guides and advisories: 1 security. Each one cited. Sources checked 2026-10-21. HTML: https://unstale.sh/npm/smtp-server/

To see which of these apply to a repository, run `npx @unstale/cli init` in it.

## smtp-server 3

### Security

- Hardens connection lifecycle handling, TLS timeouts and the DATA stream. (3.20.0) — [release notes](https://github.com/nodemailer/smtp-server/releases/tag/v3.20.0)

### Tooling

- The project migrated to TypeScript and now provides ES module and CommonJS builds. (3.20.0) — [release notes](https://github.com/nodemailer/smtp-server/releases/tag/v3.20.0)

### Fixes and other changes

- The server side of a connection closes as soon as the client leaves after QUIT. (3.20.0) — [release notes](https://github.com/nodemailer/smtp-server/releases/tag/v3.20.0)