Everything was OK with 1.06.00 but can't send with 1.0.20

I have an application that utilizes Gammu smsd files mode using Gammu 1.06.00 on
Windows XP SP2. My device is Siemens M55. Everything was OK for months until I
upgraded to Gammu 1.20.0 minimal.

With Gammu 1.20.0 minimal, no message can be sent. I looked at the outbox folder
and found out that Gammu do not pick any messages there for sending. Strangely,
if I get any incoming message, then Gammu will start to send messages normally.
It seems that incoming message is the trigger for gammu to send message normally.

Here is my smsdrc:

[gammu]
port=com6:
connection=at19200
[smsd]
commtimeout=1
sendtimeout=10
deliveryreport=sms
inboxpath=C:\Documents and Settings\inbox\
outboxpath=C:\Documents and Settings\outbox\
sentsmspath=C:\Documents and Settings\sent\
errorsmspath=C:\Documents and Settings\failed\
inboxformat=standard
transmitformat=auto

Do you have any idea? I am confused because nothing else was changed, I only
replaced Gammu.exe from version 1.06.00 to 1.20.00 minimal.

Thank you beforehand.