LibreOffice (5.1) under Kubuntu neon (16.04) can't read ANY docx files

I just recently had a slow disk crash meaning I had to upgrade my server with a new disk. I upgraded to a slightly newer version of Linux along with (presumably) a new version of LibreOffice and absolutely no .docx files open anymore.

As an example: here is one:

https://www.cise.ufl.edu/~nemo/plc/refs/HomePlug%20GP_Specification_Ch1_v1.1-Jan_23_2012%20DRAFT.docx

Every single docx file that I could formerly open ends up with:

The file XXXX is corrupt and therefore cannot be opened. Here’s a screenshot:

https://postimg.org/image/tr9f21305/

since I don’t have enough “points” just to inline the image.

I know what happened.

LibreOffice is installed, however, that doesn’t install Writer. In fact, when you try to open Writer, it will crash, on everything you try to open it with.

It turns out, that the program is “swriter” which is installed somewhere like this: /usr/lib/libreoffice/program/swriter.

You can install LibreOffice Writer from the software center.