Graphs are incompatible between 8.0 and 7.1 (by the way, for the benefit of others who might stumble into this thread, we are referring to taking a .UIR saved in 8.0, for example, and loading it in an earlier version of CVI. But the reverse will always work).
To answer your question about the known issues, keep in mind that officially none of it is supported. There are two many little changes that always take place from version to version -- bug fixes, other features, etc -- so that long ago we decided that we would not claim to support opening a UIR file in an older version of CVI. In some versions, when the severity of the incompatibility is large enough, we enforce it via an explicit warning message -- this was the case between 6.0 and 7.0, and between 7.1 and 8.0.
Having said that, at the time we created the 7.1/8.0 incompatibility, we realized that this was a problem for a lot of customers, since not everyone upgrades at the same time, and people with different versions of CVI sometimes need to share .UIR files. So we addressed this in 8.0 by providing an option to save a .UIR in 7.1 format. This is what we are planning with all future versions, whether there are explicit compatibilities or not (although unfortunately, we can't go back and save in 6.0 format or earlier).
Luis
