On Client Computer
You have two options for changing the INI settings on the client. The first is to open the client GUI in expert mode and change the values as shown below.
The second is to edit the INI file, using an editor such as notepad, and change the entries for retention and/or versions and save. The values are documented here.
On WholesaleBackup Server
You can change the retention and/or versions values on a WholesaleBackup Server by going to the Dashboard->Accounts tab, and selecting the "Account:" and "Computer:" you wish to change these settings for (from the pull-down menus on the tab) and then clicking on the "Settings" tab, and then modifying the settings and clicking on the Save button. When you click on the "Save Settings (.INI)" button the client's INI file will copied to that account's staging area at the next backup/restore the client will pull down the .INI file you edited and utilize it for a subsequent backup.
If you use the "Settings" tab to change any of the user fields (shown on the Contact tab) in lower half of the window pane, these settings will not be updated in this server GUI until the client has downloaded the changed .INI and reconnected to your server to backup or restore.