Well, first, welcome to the forum and HELLO to you too!
The route from Irun to Burgos is neither Via de Bayona (Bayonne-Burgos) nor Camino Vasco del Interior (Irun-Sto.Domingo de la Calzada). So, what route are you asking about exactly???
Anyway, there are some info here:
https://www.caminodesantiago.me/community/forums/camino-vasco-del-interior.57/ as you already know if you posted your inquiry there.
And to answer directly to your question - I don't know about the app, you can just go with old-fashioned guides and maps and you'll be fine!