It is always a challenge when a new version of Photoshop is released to transfer all the filters and or plugins. Some companies immediately put out new version which will install in the new Photoshop version through the installer. Of the filters I own, onOne Software has a new installer for Perfect Photo Suite 8.5; Alien Skin Software has a new installer for Snap Art 3 and Snap Art 4 and Exposure 6; Filter Forge has new installers for Filter Forge 3 and 4; and Nik Collection has a new installer called nikcollection-latest.exe which you can access from "Try now". An explanation can be found by clicking on the link. Below is the explanation from that page:
"What if I don't receive the auto-update?
To update your software manually, please download the latest version of the Nik Collection from Google.com/NikCollection. If you previously had a registered version of the Nik Collection installed on your computer, downloading installing the trial from the homepage will simply update the files for you. Make sure that all host applications are closed, run the installer, and your plug-ins will be back in place once you re-open the host."
I had to use basically three methods to install my filters. Fortunately, I had to do it with Photoshop CC from Photoshop CS6 (64-bit) so I had a feeling for how to do it.
The first method I described above is the easiest. The next method worked with filters from AutoFX Software. Here I just copied the .8bf plugin to the corresponding directory. This can work with other filters as well.
The third method sometimes takes trial and error to decide on the shortcut. I made shortcuts of the three DTF filters that I have. Notice that I created shortcuts from the folders. This might not be the only way to add plugins when there is no specific installer, but it is one I found worked for these filters.
If you do not have a previous versions of Photoshop, I suggest you contact the companies or look on various forums.
I hope this will save you time and effort.