1.

Version compatibility. FRED is not forward compatible, so documents (.frd files) generated in a current release cannot be opened by older versions of FRED (ex. a FRED file generated in version 16.112 cannot be opened by FRED version 15.90).  However, FRED script files (.frs) can be opened by any version of FRED. In general, there are new script commands that are present in the newer version of FRED that are not recognized by the older version of FRED. These script commands must be commented out in the script file in order for the script to compile and execute in the older version of FRED. If the script compiles in the older version of FRED, then it can be executed to rebuild the FRED model from the newer FRED version.

2.

Transparency and learning. The "FRED-out" script file contains all of the script code necessary to completely rebuild the FRED document. This means that the relevant script commands for any entity in the model must be present in the exported *.frs file, giving the user an opportunity to see the code required for constructing a particular entity in the model. Relevant blocks of code may be copied from the FRED-out file and reworked into custom scripts as necessary. 

1.

Open a new FRED document.

2.

Open the exported *.frs script file.

3.

Check for syntax errors (due to FRED version changes) by selecting Script > Check Syntax from the main menu.

4.

If a syntax error is found, comment out that line of code in the script.

5.

Repeat Step 4 until there are no more syntax errors.

6.

Execute the script by selecting Script > Run from the main menu.

7.

Switch to the FRED document created in Step 1 to confirm that the model has been rebuilt.