[Dovecot] Change in LAYOUT=fs between 1.2.9 and 2.0.19?

[Martijn]

While testing an upgrade from Dovecot 1.2.9 (on Ubuntu 10.04 LTS) to 
2.0.19 (12.04 LTS) I encountered the following change in behaviour:

In both setups, mail_location is defined as follows:
mail_location = maildir:~/domains/%d/%n/.Maildir:LAYOUT=fs

No other mail_location-related settings are set in the config.

On 1.2.9 this leads to new mail being delivered to this example directory:
/home/username/domains/example-domain.ext/webmaster/.Maildir/INBOX/new/

On 2.0.19 the exact same mail_location is set, but new mail is now 
delivered to:
/home/username/domains/example-domain.ext/webmaster/.Maildir/new/

Notice the missing /INBOX/ in the path on 2.0.19.

I found no mention of this change on 
http://wiki2.dovecot.org/Upgrading/2.0 which first lead me to suspect 
this was a bug in 2.0.19.

However, while browsing the 2.0-wiki I found a page which sheds some 
light on the behaviour that is to be expected from Dovecot 2.0.x. Quote 
from http://wiki2.dovecot.org/MailLocation/Maildir#Directory_layout > 
"Mailbox directory name":
"Without DIRNAME, INBOX will be stored at ~/Maildir/{new,cur,tmp}/, but 
when DIRNAME is specified, we get an extra path component INBOX/ 
immediately prior to the DIRNAME value, so in the example above INBOX 
would be stored at ~/Maildir/INBOX/mAildir/{new,cur,tmp}/."

I then changed mail_location to have an empty DIRNAME, like:
mail_location = maildir:~/domains/%d/%n/.Maildir:LAYOUT=fs:DIRNAME=

It appears this fixes the problem for new mail arriving (haven't tested 
other folders yet).

Questions:
1. Is this a deliberate change in behaviour between the two versions? If 
so, may I suggest adding this change to the Upgrading to 2.0 wiki page, 
because I was unable to find the relevant info quickly.
If not, is this a misconfiguration on my side, or a (known) bug in one 
of the two versions?

2. Is the DIRNAME=(empty) a good solution, or is it unusual/hacky to 
leave DIRNAME empty? Any particular problems I may expect using this 
configuration?

Thanks in advance for your help.

-- 
Kind regards,

Martijn