I am looking into Epubor now as i had to abandon my Amazon Kindle due to no longer able to download books. My Kindle too old. Really happy with Kobo. I switched to Linux awhile ago.
Seems to me that Epubor is made for people who do not like the normal digital dynasties ruling over them. I really like to challenge you to stay the course and offer a paid Linux version.
Linux is gaining popularity because of Windows last patches and other problems.
I moved to Linux last month and I am sad that your software does not work anymore!