Dovecot supports more hashing algorithms than currently supported by ViMbAdmin's Mailbox class. Switching over to the hash() function that comes with PHP will enable a large variety of hashing algorithms, notably more secure ones such as sha256 and, theoretically, even better ones in the future as they become available.

I am currently using sha256 as the hashing algorithm for the enhanced security that it offers, and this was the impetus in proposing this enhancement request. I am willing to contribute a patch if this is deemed meritable.