Check page 211
. The very first date was 2016. I believe it was only more recently they said late 2016/17 and only now (or a few months ago) spring 2017.
Yeah, initially the project was meant to be finished by late 2016, but I guess they decided to play it safe and pushed back the opening date to 2017.
In other news, the park has closed for the season until March and around Stampida some tress have been taken down and some new footers have been poured, which means that Stampida is going to receive another retrack. I don't know if they are going to finish the entire track in just 2 months or they are just going to retrack another portion. There were also some rumours of PA getting rid of the awful Kumbak trains and replacing them with GCI Millennium Flyers. After all, this season Tomahawk (the junior CCI) has recevied Minillennium Flyers and the feedback has been really positive...