The highlights of the 1.7.0 release are:
Fine-grained parallel incomplete LU factorization preconditioners (based on recent paper by Chow and Patel)
Fast sparse matrix-matrix multiplication (based on recent paper by Gremse et al.)
Improved performance of sparse matrix-vector products
Fine-grained parallel algebraic multigrid preconditioners for CUDA, OpenCL, and OpenMP
Conversion between vectors and matrices of different numeric type
Lanczos eigenvalue solver now optionally also returns eigenvectors
Interface to/from the Armadillo library
A full list of changes is available at http://viennacl.sourceforge.net/doc/changelog.html