Let's take a couple of the new FileMaker 10 functions as an example of how the FileMaker Server version is relevant. If we go to the file that is opened on 10 and hosted on 10 and go have a look at our field definition, what we have here are three calculation fields that are using some of FileMaker 10's new functions, like the code function, the character function and the get documents path listing. So when we input something in these particular text fields, we know the script trigger will run but these calculations evaluate properly. So now what will happen if we go to the file that is opened in 10 but hosted on FileMaker Server 9? If we input some text in here, we already know that the script trigger will work but we see that the functions themselves also work. In this case because the functions are executed by the client. However, if we now force FileMaker Server to evaluate that calculation, and we can do that by making a change to the calculation itself, by making a change to the calculation, we are forcing FileMaker Server to re-evaluate this calculation. If we commit our changes, then we see that FileMaker Server does not know what to do with this new function. And the same thing of course applies when we go have a look at the file and open in FileMaker 9. So although this file is hosted on FileMaker Server 10, it is opened in 9. When we go into the field definition, we see that FileMaker 9 has no way of knowing what that function is all about. It just says Function Missing. And the same applies with scripts. If we are using scripts with unique FileMaker 10 features, when we open them in 9 we'll have big unknowns. So when this script fires on FileMaker 9, if it runs in FileMaker 9, then these unknowns will be skipped. This may cause problems with incomplete data records or worse, changing data in existing records instead of creating new records or maybe even worse still, deleting records that you didn't want deleted. In conclusion, there are potential issues when mixing and matching Pro and Server versions so be very conservative about using new features in mixed environments like this. The best practice is to use a checking routine with the gets application version in your files so that only users with the correct version of FileMaker Pro get access.