We don't support it at the moment. Adding fonts is on the roadmap, but, unfortunately, I cannot give an ETA for this. What fonts would you like to have, we may be able to add those to Termius?
Not the OP, but I want PragmataPro but it's a commercial font (so I need custom font support for that), so at least having Iosevka with ligatures support would be nice :-)
I have been trying Termius on and off for a year (I subscribed), but still couldn't switch away from Blink due to lack of custom font support and inability to map Capslock to Ctrl (but I solved this by using HHKB with my iPad, which has Ctrl in Caps position)
Additionally, please, please consider adding traditional TOTP. I don't like Authy, because its initial authentication requires SMS, and the fact that Authy acts as middle-man between me and the service (e.g. to delete non-TOTP Authy token, the service need to call Authy API to disconnect the user before _I_ can remove the token from my phone)
This is a bit of an edge case, but I want to be able to use an ANSI friendly font for Telnet BBS'. At the moment, the supported fonts just render garbage. It would be ideal for me to select my own font as I find it unlikely you will add 'unscii 16-full'.