Andy,
In the simple and short form, what happens with the ACR (Adobe Camera RAW) module is that it gets updated with regularity, to accommodate the camera mfgr's. changes for their newer models. That ACR works within the host program, such as Ps, PsElements, Lightroom, etc.. At a point, Adobe ceases to support older host program versions. When that happens, the user has a few options:
Upgrade the host program version
Use another host program, such as PsElements or Lightroom
Use the free DNG converter, per Curt's suggestion. That is not host program dependent
Glad that the DNG Converter works for you.
Good luck,
Hunt