This major new release of ITensor is the first official release to require C++11 compiler support (approximately the following compiler versions: gcc > v4.6; icpc > v15; clang > v2.9). Requiring C++11 allows us to start making many key improvements to ITensor such as allowing arbitrary numbers of function arguments; improving memory safety through features such as unique_ptr and shared_ptr; and removing dependence on boost. In this release many internals have been redesigned and many bugs fixed. The uniqueReal system for comparing indices is gone as it occasionally led to incorrect comparisons in codes using many indices. ITensors and IQTensor now have simpler data storage layouts. One major new feature is the AutoMPO class. AutoMPO provides a "pencil and paper" interface for creating MPOs, both for Hamiltonians and for other sums of local operators such as orbital creation/annihilation operators.