How to convert ".doc" file to ".docx"?

Question

ASP.NET

Good afternoon, colleagues.
My method receives files of the ".doc" format, I need to read them and display the contents of the file.
A solution that is quite satisfactory is to convert the file to the .docx format" and read it with the documentformat.openxml library.
The Microsoft.Office.Interop.Word library is not suitable, as it requires the installation of the office itself. (if wrong, how to do it)
There are libraries Aspose.Words and Spire.Doc, but they are paid (there is some functionality for free, but it does not work stably)
How to convert a ".doc" file to ".docx"? ( what are the ways or solutions)
Thanks
Regards

Answer 1

There is an NPOI library, this is a port of Apache POI and there is support for Doc and DocX, but it wasn’t included in the release, you still need to find it or build it from the code, apparently it doesn’t work in the best way since it didn’t enter.
You can buy a VPS (server) to install Office there and use it as a cloud, a perversion of course, but maximum stability.
In such cases, reverse engineering can help, but if this is not a limitation of the free version and they are "curves" in themselves, then they will not help.