If you are running a version 0.5.x or even 0.4.x you cannot update to 1.0 without a full re-installation from scratch, sorry.
Updating to 1.0 from 0.6.x - First, backup everything. Second, copy your prasi data-tree to a safe location. Third, install 1.0 over 0.6.x. Finally, when the installation is complete, delete the 'new' prasi data tree and copy your old one back to its old place. This procedure will mean that only the program files, not the data files, will be changed, and this is sufficient for updating.
Updating from 1.x to 1.y - the 1.x series installer does not touch the user data portion of the prasi data tree, so it is safe to install a newer version over an older one. However it is recommended to backup the data tree in any case.