This only affects 1.6.?, 1.4 will be supporting the old Zap.
From Zaptel-to-DAHDI.txt http://svn.digium.com/view/asterisk/branches/1.6.0/Zaptel-to-DAHDI.txt?view=co :
As announced in early 2008, Digium is renaming the Zaptel telephony
interface project to DAHDI (Digium Asterisk Hardware Device Interface)
to accommodate the desires of the owner of the Zaptel trademark for
This version of Asterisk can only be built using DAHDI, and as a
result there are number of changes that will be visible to previous
users of Asterisk with Zaptel.
Second, the behavior of many modules has changed due to the switch to
DAHDI; the changes are listed below.
Incoming and outgoing channels managed by this module will be
'DAHDI' channels instead of 'Zap' channels.
All CLI commands that began with 'zap' have been renamed to 'dahdi'
All Asterisk Manager Interface (AMI) actions that began with 'Zap'
have changed to 'DAHDI' prefixes.
The ZapSendKeypadFacility dialplan application has been renamed to
The configuration for the channel driver will be read from
/etc/asterisk/chan_dahdi.conf instead of /etc/asterisk/zapata.conf.
This gives us some work to do, a quick grep on the 2.4 codebase gave me this: http://tese.se/zap2dahdi.txt
A lot of that would not break the 1.6.? support, but there are some stuff that needs attention. My suggestion is to not do anything with the GUI, but create the files / configurations accordingly. The GUI needs update as well, but could be done at a later stage.