Asterisk (Ver.

I am adding an entry to extensions_override_freepbx.conf as follows:

exten => 1870,n,SIPAddHeader(Alert-Info: info=Auto Answer)

After an amportal reload, the SIP header is not sent to extension 1870.

However when adding directly to extensions_additional.conf, the SIP header is sent.

exten => 1870,1,Set(__RINGTIMER=${IF($[${DB(AMPUSER/1870/ringtimer)} > 0]?${DB(AMPUSER/1870/ringtimer)}:${RINGTIMER_DEFAULT})})
exten => 1870,n,SIPAddHeader(Alert-Info: info=Auto Answer)
exten => 1870,n,Macro(exten-vm,novm,1870,0,0,0)
exten => 1870,n(dest),Set(__PICKUPMARK=)
exten => 1870,n,Goto(${IVR_CONTEXT},return,1)
exten => 1870,n,Goto(from-internal,1870,1)
exten => 1870,hint,SIP/1870

Is my entry in extensions_override_freepbx.conf correct?

No, you need the WHOLE context in the override not just the additional bit.