Simply download and install the free Adobe DNGconverter software. It will convert your unsupported raw files to the DNG raw format that your current PSE can't read. You batch convert a whole folder of your raw files into the DNG raw format that your current PSE can read and edit. An additional batch step, but same quality and free.
If you have some time, browse some other discussions about the same issue in this forum as well as in the feedback forum. See the "More like this" section on the panel on the right of this page. Don't expect an update to PSE2019 now, the next version is generally available end of September/beginning of October.