Each year Adobe releases a new version of Elements. Adobe only updates their current versions of software for new cameras which would be PSE15; however, with Elements, it usually stops getting updates in late Spring or early Summer because a new version is being created for release in the Fall.
Short story is that you’ll likely need to buy the next version of PSE, presumably 16, whenever it is released in the next month or three, to be able to use your camera’s native raws with it. In the meantime, you can use the Adobe DNG Converter 9.12 or newer to create DNGs from the TG-5 raw files, and those DNGs, but not the raws, will open in the older version of PSE’s ACR plug-in.
If and when you buy a new version of Elements that has ACR 9.12 or newer, then it’ll be able to work with the DNGs and the raw files from your camera, which might be confusing if you have them all in the same folder, so you might want to put the native raws in a subfolder of the DNGs, at least while you’re creating DNGs from RAWs, so you don’t get mixed up which images you’ve worked on (the DNGs for now). Don’t delete the raws, though, in case you want to work with them in the future, with some other software that doesn’t understand DNGs.
Once you have PSE16 then you won’t need to create DNGs from raws anymore.
The DNG Converter is available, here:
https://helpx.adobe.com/photoshop/using/adobe-dng-converter.html