I am using 3cx version 9. I use Yealink, 3cx softphone and Cisco phones. Everything works fine except "Attended/Announced" transfers when the transfer is from Yealink to Yealink phones. The yealink model is SIP-T22P. This happens all the time when the "attended" transfer is from a Yealink to another Yealink phone. FYI, "Blind" transfers work fine in all cases. "Attended/Announced" transfers work fine when the transfer is to a non-Yealink phone such as Cisco or 3cx softphone. I have attached 3cx server logs. One is of the Yealink to Yealink "attended" transfer which does not work. The other is a Yealink to 3cx softphone transfer which works fine. I followed http://www.3cx.com/sip-phones/Yealink-IP-phone.html and Yealink "Configuration Guide for Yealink IP Phone & 3cx" instructions.