Here is some more information on bank file versioning…
We support both backward compatibility (new code loads older bank) and forward compatibility (old code loads newer bank).
Our policy is to maintain backward compatibility for as long as possible. Presently this extends back as far as version 1.03.00 (when the new bank file format was introduced). So for example, if you have existing banks that were built with Studio version 1.05.xx, you should have no problem loading these with a future version of the library, say 1.06.xx or 1.07.xx.
We also provide support for forward compatibility, although this feature is more limited. Our policy is to maintain strict compatibility across patch releases within the same minor version. For example, a game that was compiled with FMOD version 1.05.02 will be able to load banks that were built with Studio version 1.05.09. Basically, any 1.05.xx version of the library should be able to load banks built by any 1.05.yy version of the tool.
However, we do not guarantee forward compatibility across larger version increments, such as going from 1.05.xx to 1.06.xx. That means old game code that was compiled with FMOD 1.05.xx will not be able to load banks built by the new Studio version 1.06.00 or later.
Hopefully that further clarifies how bank version compatibility works.