There are several popular versions of DNS (Domain Name System) software that are widely used to manage DNS services. Some of the notable DNS software versions include:

1. BIND (Berkeley Internet Name Domain): BIND is one of the most widely used DNS software implementations. It is an open-source software developed by the Internet Systems Consortium (ISC). BIND provides a robust and feature-rich DNS server that powers a significant portion of the internet’s DNS infrastructure.
2. PowerDNS: PowerDNS is an open-source DNS server software known for its flexibility and scalability. It offers various back-end options, including traditional zone files, relational databases, and dynamic DNS updates. PowerDNS is highly customizable and supports advanced features such as DNSSEC (DNS Security Extensions) and load balancing.
3. NSD (Name Server Daemon): NSD is an open-source authoritative-only DNS server software. It is designed to be lightweight, fast, and secure, making it suitable for high-performance environments. NSD focuses on providing authoritative DNS services and supports features like DNSSEC and IPv6.
4. Knot DNS: Knot DNS is an open-source DNS server software developed by CZ.NIC, the registry for the .CZ top-level domain. It aims to provide a secure, scalable, and high-performance DNS server. Knot DNS supports features like DNSSEC, dynamic updates, and zone transfers.
5. Dnsmasq: Dnsmasq is a lightweight, open-source DNS and DHCP server software. It is often used for local network environments, providing DNS caching, DHCP services, and network booting capabilities. Dnsmasq is known for its simplicity and ease of configuration.
6. Unbound: Unbound is an open-source recursive DNS resolver software designed for security, performance, and privacy. It focuses on resolving DNS queries and validating DNSSEC signatures. Unbound is often used as a caching resolver or as a local DNS resolver in privacy-centric setups.
7. MaraDNS: MaraDNS is an open-source DNS server software known for its simplicity and security. It is designed to be easy to configure and suitable for small to medium-sized networks. MaraDNS focuses on providing a secure DNS server with a minimal attack surface.

These are just a few examples of popular DNS software versions available. Each DNS software has its own strengths, features, and use cases. The choice of DNS software depends on factors such as the specific requirements of your DNS infrastructure, security needs, performance considerations, and personal preferences.