Since one week we have the new website of PolSARpro:
http://step.esa.int/main/toolboxes/polsarpro-v6-0-biomass-edition-toolbox/
PolSARpro 6.0 can be downloaded from here: http://step.esa.int/main/download/polsarpro-v6-0-biomass-edition-toolbox-download/
There is a new section of the forum for PolSARpro users and fans of polarimetry as well https://forum.step.esa.int/c/PolSARpro
Have fun!