I recently started trying out a new font (well, new to me) called Atkinson Hyperlegible. My friend Linus did a recent video stream all about it and I really enjoyed its features, designed around readability. I was excited because they recently released a monospaced version of this font…
… and I like to read my email message in monospace. I installed this font on my Windows 11 system but when attempting to change my setting in eM Client (under Mail → Read → Preferred font for messages) I was presented with the error:
“The selected font is not a True Type font and therefore cannot be used. Please try a different one or install a True Type version of this font.”
I mean, this clearly seems like a true type font to me. It’s a TTF file, etc. Now this is a very new true type font and it supports variable weights as opposed to discrete “regular” and “bold” versions. Could that be causing an issue?
I’d really like to be able to find a way to try this font out in eM Client. Fingers crossed! 
I realized that I didn’t categorize this when I posted initially. Not sure if this is a “feature request” or if this is a “problem displaying mail”… i’m thinking it’s the latter, since the feature of “select your preferred font for mail display” already exists, it’s just not working in this instance.
I can’t for the life of me tell why eM Client thinks this isn’t a TrueType font, unless it’s something to do with that variable weight feature, which is a slightly newer type of way to package TTF fonts.
“The selected font is not a True Type font and therefore cannot be used. Please try a different one or install a True Type version of this font.”
There is alot of eg: “non standard” TrueType fonts from doing a Google search, and so then eM Client would more than likely need to be updated to support / accommodate them correctly.
Just adding them into the OS font library, doesn’t allways guarantee “all programs see and use them correctly” when opened.
So I suspect that this new font Atkinson Hyperlegible might be one of those non standard TrueType fonts. Hopefully will work in a future update. Its an interesting font.
I’m curious, when you say…
… is the a hope for an updated to eM Client or a hope for an update to the font?
is the a hope for an updated to eM Client or a hope for an update to the font?
An update to eM Client maybe in the future, where it then might accommodate that specific font.
I would suggest you add this font as an idea in eM Client in the Sleekplan voting and ideas page.
UPDATE! 
Reaching out to my friend Linus and others led me to learn more about this topic than I had ever planned. His reply was super informative…
"Both TTF and OTF are wrapper formats to some degree (sort of like .mov and .MP4 files can contain a bunch of different video codecs)
To make things more confusing, true type is a specific font encoding standard, but that doesn’t mean that a TTF file necessarily follows a particular version of that standard which may be required for your email client? Email is also particular hairy when it comes to typography, which we can geek out over at dinner if there’s nothing better to talk about 
"
The biggest good news that he shared with me, however, is that there are static (that is non-variable) true type versions of Atkinson Hyperlegible available on this GitHub repo…
… I installed them and that worked perfectly within eM Client. So I’m good now! (And now we know what might be the issue if other folk encounter this with other varieties of variable-width fonts in the future.