At its release, the Emancipation Proclamation did not free the slaves from the four border states, Delaware, Maryland, Kentucky and Missouri, and also did not free slaves in certain parts of Louisiana, especially along the Mississippi river, which were part of the Union, including New Orleans.
However, as you know, slavery was abolished in the USA, so what was it that abolished it? The legality of the Emancipation Proclamation is debated because in order to change a law, you must pass a bill through both houses of Congress, have the president sign it, and then have it ratified by ¾ of the states.
The Emancipation Proclamation doesn't meet this criteria because it was an executive order, not a bill.
Instead, the 13th Amendment was the one that formally abolished slavery and involuntary servitude in the United States, which is why it is illegal today.
