Pjsip errors in Asterisk 11

So, on a FreePBX13 Asterisk 11 install, this exists in extensions_additional.conf

include => autoanswer-custom
exten => s,1,GosubIf($["${ARG1}" != ""]?addheader,1(Alert-Info,${ARG1}))
exten => s,n,GosubIf($["${ARG2}" != ""]?addheader,1(Call-Info,${ARG2}))
exten => s,n,Return()

exten => addheader,1,SIPAddHeader(${ARG1}: ${ARG2})
exten => addheader,n,Set(PJSIP_HEADER(add,${ARG1})=${ARG2})
exten => addheader,n,Return()

Second-to-last line there causes error

pbx.c:4444 ast_func_write: Function PJSIP_HEADER not registered

I guess it’s not doing much harm, but it shouldnt be asking anything of pjsip for asterisk 11 should it?

The error can be safely ignored. Eventually we won’t support Asterisk 11 anymore and it won’t matter.