Sig compliant BT Mesh will be supported on the CYW20719/CYW20706 initially. The CYW20719 will be introduced to the broad market and be available within the Broad Market SDK very early in 2018. The 20706 is supported today, but mesh support for the 20706 will be in the upcoming releases of WICED Studio.
Combo chip broad market support of the standard will most likely follow later in 2018.
The CYW2073X will not support Sig Compliant Mesh.