Any later version of SliQ Invoicing Plus can open backups created in older versions or in SliQ Invoicing Lite. When a backup from a different version of the package is restored into the latest Plus version, the file format will be upgraded so that the restored file can be used with all of the features in the latest issue, e.g. in V3 you can store purchase orders in a company file restored from V1 or V2.
A backup file is a complete copy of all your invoices, quotes, product details, customers and so on for a particular company. However, any custom templates are globally available to all your companies and are not included in the company file backup. Backing up your custom invoice and quote templates is simply a matter of copying the customtemplates folder under the My Documents\SliQInvoicing3 folder on your PC. Once you have defined your templates using our template editor, the templates tend not to change very often so you do not need to backup the customtemplates folder unless you make another template change.
For more information on restoring backups, especially from older versions of SliQ Invoicing, see http://www.invoicing-software.com/loading-sliq-invoicing-backups.php