Great idea. I haven't touched Res 5 myself since about a year before 6 was released, but I guess I'm not your target audience
Why did you change the minimum BPM from 2 in R5 to 20 in R6?
No real reason
I had to use two OSC senders with different port numbers, is that a restriction of OSC?
Why can't the two versions of Resolume listen on the same port?
When using OSC, you enter in a server/client relationship. Resolume is the server and you're the client sending messages that change the state of the server.
A server re-using the same port already in use by another server is technically possible, but generally frowned upon. Unless both servers have indicated that it's okay for the other to also use the port, you cannot be sure that both will receive the data. Also, if a server that was previously 'hogging' the port was to suddenly disconnect, the other server can receive half a message, possibly causing all sorts of weirdness.
This is of course really only an issue when you're dealing with applications where receiving half a message or no message makes the difference between life or death. You could argue that in the case of Resolume, we should just always try to share the port and hope for the best.
It might be that the benefits of having shared ports outweigh the frustration of having to figure out that another application is hogging the port. So far, we've stuck to "best practices", which at least makes it very clear when your OSC input port is able to receive something and when it's not.