Can files I created with one version of Prism be opened by another?

Opening files made with older Prism versions with newer versions. 

Every version of Prism can open files created by earlier versions. The only exceptions were that Pris 4.0a and 4.0b (mac) and 4.00 and 4.01 (WIndows) could not open files created by Prism 1 (fixed in Prism 4.0c and 4.02).  

Opening files made with newer Prism versions

In general, older versions of Prism (version 4 and later) can open files made with newer versions. But it all depends on what features you used in the newer version that weren't in the older version.  If your file has tables with more columns or subcolumns than the older version can handle, those tables will be empty when you open the file. If the file contains analyses that the older version can't perform, they will be frozen. If you use formatting choices that the older version doesn't recognize, usually Prism will do something sensible (like changing a pie chart into a bar chart, changing semi-transparent colors into solid colors)...

???????There are no special commands for saving a Prism file in an older format. 

The location of analysis results may change between versions

When you open a Prism file on a version different than the version it was created on, results also may appear on different rows of the results tables. This means that results tables embedded on graphs may no longer show the results you care about, and scripts may export the wrong values. You may have to do a bit of clean up to make the files work as intended.

File compatibility between Windows and Mac Prism files

The Windows and Mac versions of Prism use the same file format, and you can go back and forth without any special conversion.

Compatibility of Prism objects saved within other documents

On Windows (but not Mac), when you paste a Prism graph or layout within Word or PowerPoint (or some other programs), you can paste just a picture, paste a link, or embed a Prism object. If you paste a link or embed an object, you can then double click on that image to edit within Prism. This works only if the correct version of Prism (or the free Viewer) is installed. If a Prism 5 object is embedded within a Word document, for example, double-clicking to edit that object will only work if Prism 5 (or later) is installed on that computer. Double-clicking on a Prism 4 object will open Prism 4 if it is present on that computer, or Prism 5 or 6 if Prism 4 is not present.