Yes, it's still possible and you can get it from this page HERE.
Be aware that this free version still has many bugs and compatibility issues and that DxO only offers support for the paid version available HERE.
For a better customer experience, we strongly advise you to upgrade to the version available in our online store.
Online Support is available only to customers who have purchased the paid version of the ‘Nik Collection 2018 by DxO’ available since June 6, 2018: plugins version 22.214.171.124 64x (v1.2.14).
Previous versions cannot be the subject of a request for assistance, because we have not developed them. However, you will find information on some of the known issues in the FAQs below.
For any stability issues, compatibility with the latest Adobe CC products and the latest Mac OS, and for future updates and our support, we strongly encourage you to upgrade to the latest version of the Nik Collection by DxO available here.
Thank you for your understanding.