Chart diagram files created in version 2 will have a version 2 stitch library as the 'active' stitch library. When opened in version 3 the chart and written instructions will be exactly as if they were opened in version 2 and can continue to be used as before.
In the Stitch Library and Text Templates tab of the Edit Diagram Properties dialog, the 'active' version 2 stitch library will not be displayed in the drop down list for stitch libraries but will instead be displayed separately. Only stitch libraries in the version 3 format will be listed in the drop down and are available for selection.
If you now select a version 3 library from the drop down list a warning message will be displayed to let you know that it will not be possible to change back later. We recommend that you make a copy of your file before you make this change.
Note that if your chart diagram file contains any of the increase stitches that have been updated for version 3 the written output will have changed when you update from a version 2 to version 3 library.