A real short post to keep track of the new config for TACACS+ on Cisco devices. It's not really that new, but it avoids the deprecated warning!
tacacs-server host <server ip> key <my tacacs key>
Replacement 'new' config:
tacacs server AUTH address ipv4 <server ip> key <my tacacs key> ! aaa group server tacacs+ TAC_PLUS server name AUTH