It depends on what sort of mass update you are looking for?
There is a feature in Maximizer to do a Global edit, which can update fields on-mass.
create a list of all the Client/Companies or Contacts that you wish to update and go to Edit select al then Edit>Global Edit and which ever field you choose and which ever entry you type (or if it is a table, which item you pick) will be globally edited into each entry.
Regards
CABC Support