>   autoupdown=no
> 
> (where yes is the default and typically what you want).

I should probably expand this a bit: this is the same behaviour as before,
but if you don't expect it, it may cause you costs, so beware!

Here is what happens and the reasoning:

Why do we need this?

Isdn interface can not work before isdnd runs. They are typically configured
via /etc/ifconfig.ippp0 (for example) and marked down there. Once isdnd
runs, this interface would be usefull - if only it would be marked up.

So, by default, isdnd recognizes an interface with valid isdn configuration
and proper IP configuration (i.e. at least one real address assigned) and
marks this interface up.

This is what you want if you have a flat rate connection to your ISP or
have set the "link1" (aka dial on demand) flag for ippp interfaces (irip
Interfaces always do this, due to their ~non existent connection setup
time).

You do not want this, if 

 - you pay by time for your isdn connection 
 - AND have configured the IP for a normally unused interface controlled
   by isdn via /etc/ifconfig.* files

In this case you formerly would have added "isdn_autoupdown=NO" to 
/etc/rc.conf (or overriden the default isdn_interfaces variable).
Now, instead of that, you add "auotupdown = no" to the /etc/isdn/isdnd.rc
configuration entry for this interface.

If you had one of those variables overriden in /etc/rc.conf, please make
sure to check and update your isdnd.rc !!!

Martin