A very old, unsupported version (1.2.11) was once released for free by Google and can sometimes be found on Archive.org
Installation: Download the Nik Collection installer from your DxO customer account. Color Efex Pro 5 Activation Key
: When you purchase the Nik Collection from the official DxO shop, you receive a perpetual activation key via email. This key allows you to use your specific version of the software indefinitely without a subscription. A very old, unsupported version (1