tentative date? I was supposing this project was developed since 2013 and announce was made when everything already tested on testnet? Some major problems occours?
Theoretical development started in 2013. Code was written in April, 2014, so that marks the date of the beginning of the practical implementation of the work. Tentative in this context does not mean 2-3 months of delay. As you know, software development is a complex process and requires a lot of testing and examination. There was a post about it
here. The delay happened because of the overwhelming interest and the fact that every participant's application receives individual attention.