Undocumented change of 'blf+sd' behavior between 7.5.3 and 7.5.4 fw

[Dan Lukes]

Imagine button with Extended Function defined like this:

fnc=blf+sd;ext=*F1234@$PROXY;sub=*D7*1234@$PROXY;vid=1

according documentation, the button should subscribe to line *D7*1234 to show it's state ('blf' function) and dial the *F1234 when pressed ("sd" function)

Unfortunatelly, real SPA50XG phone with firmware 7.5.3 or older doesn't work as described. It dial *D7*1234 when pressed ignoring ext= parameter at all.

It has been fixed in firmware 7.5.4, but such change is not documented in Release Notes.

Someone may rely on old misbehavior, so be carefull.

You have been warned.

[Dan Lukes]

Masarakš! It still doesn't work correctly.

On firmware < 7.5.4 the device ignore ext= at all. It will dial sub= when button pressed.

On 7.5.4 firmware the device will dial ext= when button pressed, but the notification doesn't work as long as ext= value desn't equal sub= value. Imagine following configuration:

fnc=blf+sd;ext=*F919@$PROXY;sub=*D7*4403@$PROXY;vid=1

The device will correctly subscribe:

SUBSCRIBE sip:*D7*4403@10.250.254.1:5060 SIP/2.0

but then it ignore notifications:

NOTIFY sip:DEV-4403@10.20.12.9:5060 SIP/2.0

...

Content-Type: application/dialog-info+xml

confirmed

Such notifications are silently ignored (including no syslog message, even at highest debug level). Button will blink yellow.