According to Wirtualnemedia.pl, Polish National Final will take place on 11th February 2017 in Warsaw and the winner will be decided jointly by viewers and jury. This formula is back for the first time since 2009. In years 2010-2011 and 2016 Poland picked the Eurovision entry using the televoting only. Worth to mention that Poland missed the final of Eurovision every single year when the winner of National Final has been decided by viewers and juries, except of Isis Gee in Belgrade 2008.
The official rules of National Final are not online yet but TVP will most likely confirm everything next week and the submission period will be open. All singers and composers will have only less than a month to send their songs as TVP is about to close the submissions on 20th January 2017. It is still unknow if foreign artists/composers are permitted to enter the National Final.