dovecot - May 2006 - two concurrent dovecots

Hello,

Is it safe to have two concurrent dovecot processes to access the same
maildir? I have a stock RHEL version (0.99.11) used by users, but I also
want to test 1.0-beta together wth postfix for SASL. Is it safe to access
the same maildir concurrently with both dovecots (say, the old one via
webmail and the new one via remote client)?

Thanks,
Alex