DBP verions are on a supported/unsupported basis. Only the version advertised as being supported is guaranteed to work. There isn't anything that prevents you from upgrading from a more recent version, if that's what you're asking.
If you do this, new commands which didn't previously exist obviously won't work. But if there is one that you need it's possible to wrap it yourself using the included plugin SDK. Documentation for this is in the help file. Adding new commands is as easy as editing a text file and does not require any programming knowledge. The SDK tools will generate the source code for you.
The current supported release (at the time of this post) is for PB 4.31 and DBP 7.3. There are no problems using DBP 7.4 with the current release that I'm aware of. The next version will support PB 4.40 and DBP 7.4.