Ok, some file editing is needed now to make it work.
On XMC, copy sflow,pol.
cp /usr/local/Extreme_Networks/NetSight/appdata/Purview/Fingerprints/sflow.pol /tftpboot/
On Analytics, edit file /opt/appid/conf/appidconfig.xml and change interfaces to be like:
Restart analytics or appid after this.
On XMC go to analytics, configuration and on your engine add an application telemetry source (the switch) and enforce.