SMP2, introduced in early 2010, uses a purely thread-based system, which fixed a lot of the problems associated with SMP1. MPI is no longer required, and we deprecated the original MPI-based v5 SMP client in favor of SMP2 since it is so much easier for donors to use. SMP2 also brings a new points scheme, which is summarized in the new points FAQ.
SMP2 is now the basis for our current SMP methods, which are commonly used by default in the V7 client software.