Windows 7 and Server 2008 R2 had IPv6 enabled by default. No action is required to enable IPv6. Internet Connection Sharing (ICS) is disabled by default, and should be disabled if found to be enabled on any network interface as described here. They also had a DHCPv6 client enabled by default.

How do I enable IPv6 on Windows 7?

IPv6 and Windows 7

1. In the bottom left corner of your screen, select the Start icon.
2. Select Control Panel.
3. Select Network Sharing Center.
4. Select Change Adapter Settings.
5. Right-click your network connection.
6. Select Properties.
7. Enter the administrator password or confirmation, if prompted.

Will older versions of Windows OS support IPv6?

Internet Protocol version 6 (IPv6) is enabled by default in all versions of Microsoft Windows version 8 and later, and Server versions released in 2013 or later. No action is required to enable IPv6. … Server versions have a DHCPv6 client enabled by default.