No, that's completely wrong. Downcoding has nothing to do with ICD versions. This article is talking about changes to the billed HCPCS (including CPT) codes to ones with lower rates. Most US healthcare claims do include at least one ICD-10-CM code to indicate the diagnosis but this is just supporting information. Payers don't change diagnosis codes. ICD-11 isn't used on US claims at all, although it might be adopted in a few years.