Tizen Developers

I am currently building a web app for TV devices. 

Unfortunatley, the new physical TV device I bought recently is running Tizen 4.0, which is very old now and runs Chrome 57 inside. (Also requiring usage of ES6/ES2015)

I have been unable to get our custom fonts working. And I have also tested a sample app provided by Samsung.

Please could someone confirm for me that custom .ttf fonts do NOT work on Tizen 4.0 web apps?  
So then I can ignore this issue on Tizen 4.0 and cross my fingers that it will work on newer TV models. 

(I have tried to run a software update to try and upgrade my TV, but the option is not active for me to select, so I assume it cannot upgrade any further.)

Thanks.