Simple Invoice is stand alone software and does't need any additions which can consume system resources eg. SQL Servers or Microsoft Access.
Simple Invoice was designed for latest Windows systems and works on:
Download package size 1.5 MB.
Current version: 3.8.2 (Revision(3)) (release date: 2018/04/16)
If you has been using previous version don't worry about your data. Setup file overwrite only program files. You data is safe.
NOTE: If your windows sytstem during installation displays a message saying "Windows protected your PC" don't worry. Simple Invoice is safe and isn't any virus or bad application which can harm your computer. It's because Simple Invoice is a new software and isn't digitally signed yet. You can simply allow install it by click "More info" and next "Run anyway".