single quotes in xhtml output

[Cuyahoga Falls]

I have been using LyX for years. I am now using LyX 2.3.4.3 on a Lenovo 
laptop running Windows 10. I also run a slightly older version on a Sony 
laptop running Linux Mint 18. The subject of my concern exists on both 
computers.

I often want to export to xhtml. However, when I do so, single quotation 
marks and apostrophes (`) and (') do not get converted to curly 
typographic quotes. Double quotes get converted just fine. Also, when 
exporting to html, all quotes are properly converted, but I prefer the 
single file output of xhtml.

I was looking through the bugs at LyX.org and couldn't find anything 
mentioning this problem, but it has been around for so long that I have 
to believe the LyX developers are aware of the behavior.

Do any of y'all know if this is a known bug, and whether or not it is in 
the process of being addressed?

I just thought I would ask before creating an account to log in a bug 
report.

Virgil