Sure you can, but CVI supports only one version of the runtime engine (RTE) at a time since 8.0 I think it was, and that will always be the latest version that's installed.
So, if you are making distribution kits with your older version of CVI, you'll discover (or not) that you're distributing the newer version of the RTE with it.
This may or may not be a problem for you - but if you think you have any RTE version related issues, I'd be quite cautious. I have found it really hard to fully remove the RTE, or to even figure out what it consists of, or where everything is. This can be further complicated if you distribute with the RTE in the same folder as the executable. NI's theory is that any old application will run just fine on a newer RTE. NI does a poor job, IMHO of describing how all of this works - I wound up learning the hard way. I'd worry that if you install the 9.0 RTE, you'll wind up using going forward even if you think there's a problem with 9.0 and remove CVI 9.0 from your system.
If CVI were a more capable tool, it would allow the user to specify the RTE version to distribute and use with an application, and check for consistency of the app against the RTE version chosen.
The one situation I'm not sure about is what happens, if, say, you have a CVI 9.0 RTE in the system folder, but distribute an app with the 8.5 RTE placed into the application folder. What version of the RTE is used? Will everything work as expected?
Another word of caution - if the 9.0 is an eval version, don't build anything with it that you need to work - the executables produced have a time-bomb in them that will cause it to quit running after a time trigger (actually, two different triggers I think). This is especially insidious if you build any dll's with the eval version and they wind up on your system - it can be a nightmare rooting them all out. I had naively thought that after I went to a full license on the newer version that the previously built apps would be OK but that's not the case. Again, NI does a poor job of explaining this to users, IMHO.
So, I'd recommend installing 9.0 on an entirely separate system - especially if it's the eval version. And remember that you'll wind up with the 9.0 RTE on that system, even if you remove CVI and reinstall the 8.5 version. Remember to remove anything built with an eval version of CVI.
Menchar
