Need to know what was the last OS before Akai quit making on

Hi 4K Gurus,

I just bought Akai 4000 a used one but in very good condition. I had MPC 2500 before but 4K is just a different machine which i like a lot, but the OS on my 4k is 1.71. I am in search of the most latest OS before they stop producing 4K and its OS.

Also, i am having trouble using CD drive, It shows light, it opens and close and takes the CD but when i try to load content of CD machine shows empty drive......any suggestions why it does that?

moniz :

1.71 is the latest OS, there will be no more updates