[imp] Address Book

[VA Today]

I am using webmail IMP H3 (4.1.3) but do not appear to have any contact
folder/address book.  I have changed the options to save addresses to
default address book but unable to locate the address book (does not appear
in either folder listing or menu).  I have been given access to horde
webmail by my client's web developer, but he is unable to explain why we do
not have any address book option.  Is it something to do with the version we
are using?  

Apologies if this is a daft question - but I am only a user, not a developer
and not sure where/who to ask for help from here.

Thanks
Alison