The Nano network is designed to allow peering between multiple versions of the node software, with older versions being periodically de-peered. The active versions currently peering and being supported can be found in the Node Releases page of our documentation: https://docs.nano.org/releases/node-releases/

In December 2018 the Nano node codebase was audited by Red4Sec and found to have no critical vulnerabilities. The following vulnerability was resolved:

Risk: High
Report Location: Pages 34-35
Resolution: Pull Request #1563 in release V17.1

All other notices from the report were classified as informative and are continuously improved on over time (e.g. code styling). The full report is available here: https://content.nano.org/Nano_Final_Security_Audit_v3.pdf

To report security issues in the Nano protocol, please send an email to security@nano.org and CC the following security team members. It is strongly recommended to encrypt the email using GPG and the pubkeys below can be used for this purpose.

For details on how to send a GPG encrypted email, see the tutorial here: https://www.linode.com/docs/security/encryption/gpg-keys-to-send-encrypted-messages/.

For general support and other non-sensitive inquiries, please visit https://forum.nano.org.