Where to download Lightroom 5.7.1???

I just bought a new computer and installed Lightroom 5.2 on it with the disk I had bought several years ago.  I want to update it to 5.7.1 like on my old computer but apparently Adobe has discontinued downloads to it on their public site.  I already searched the forums here and also spent an hour with Adobe Support and they just told me to upgrade to CC but I am happy with the old version for now.  I see that it is available on non-Adobe sites but I don't want to download anything dangerous.  Does anyone have any advice?  Thank you...