There seems to have been contradictory information on the INE website: the new threshold for a party to retain its official status is 3% of the vote.
Which means that two parties will likely not be with us in 2016. The Humanists are definitely out. (I suspect that this is a good thing.) The Labor Party is in trouble: the current count puts it at 2.91% of the vote This isn’t the first time that Labor failed to pass the bar: it lost its status in 1991, just a year after being founded, but regained it the next year.
The same could happen this time; after all, it is relatively easy to register a party. Or its membership could disperse, moving over to Morena or the remnants of the PRD. Either way, I doubt it matters much; the P.T. has only been important in coalition with other leftist parties.