Nik Collection 4.0 was announced recently but comments here say that if you have a previous version it always shows an update warning that can’t be turned off.
Within a couple weeks of usage, I received the on-screen notification when launching the software below telling me to update. However, clicking on that “Install Now” button neither downloads nor installs a software update but instead, takes me back to the DxO website and prompts me to purchase brand new software.
If you’re curious, the original Nik Collection that was made free by Google in 2016 still works. You can grab it on Mac and Windows from this page at archive.org.