Retired in ISO 639-3: Merge into Zo [zom].
Excerpt from change request document:
Yos is the English plural form of the name 'Yo', which is just another pronunciation of 'Zo'. Yos/Yo is not a separate group or a separate language. It is the same as 'Zo'. No references to the 'Yos' exist apart from an obscure alleged reference in the 1983 Census of Myanmar. Yos [yos] should be retired from use, since it is equivalent to Zo [zom].