You can still get the original NIK software at no cost. DxO who bought NIK from Google make the original version freely available (except they do collect your email address). Unsurprisingly they no longer support it, but do offer a paid upgraded supported version.
It is also worth knowing that the modules do NOT need to be integrated into other applications such as Photoshop or Lightroom, they may be run directly by creating a link to the executable file within your computer’s file system — typically something like C:\Program Files\DxO\Nik Collection\Silver Efex Pro 2\Silver Efex Pro 2 (64-Bit)\Silver Efex Pro 2.exe on Windows machines.
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