DIFFERNEC BETWEEN PICO & UDS

Hi Experts,

Could any one kindly help me in explaining the differences between UDS and PCo i.e.

1.) Which one to use and when

2.) The main differences between the two

3.) Advantages and Disadvantages of one over the another

Also, Could any one kindly outline the procedure of migration from MII v11.5 to v14.0 like what all needs to be done and what should be taken care of while performing it.

Thanks,

Praveen