[Zope] upgrading to 2.1.3 and acl_users

[Cornelis J. de Brabander]

Hi,
I have performed an upgrade from 2.0.0 tot 2.1.3. (Windows NT) by copying
the data.fs.* to the var directory of the new Zope install. Both services
were stopped during copy. All went well, but in all acl_users folders the
passwords appear to have disappeared: in the manage screen of acl_users, the
password and confirm fields are empty. However, the site functions as it
should: where required access is only granted after inputting the original
password that belonged to a user in the 2.0.0-version. Does anybody have a
clue about what could have happened, respectively whether this is a
forerunner of trouble?
cb