Two new ideas about PLS appeared recently: an extension to take into the account the rank order of factored groups, called PLS-ROG  and comparative study of missing data approaches .
H. Yamamoto, "PLS-ROG: Partial least squares with rank order of groups", Journal of Chemometrics, vol. 31, pp. e2883, 2017. http://dx.doi.org/10.1002/cem.2883
A. Folch-Fortuny, F. Arteaga, and A. Ferrer, "PLS model building with missing data: New algorithms and a comparative study", Journal of Chemometrics, vol. 31, pp. e2897, 2017. http://dx.doi.org/10.1002/cem.2897