Technically, it is open to wider interpretations than past teaching. The text itself can be used to support the “traditional” teaching on sex outside of marriage and mortal sin, but because it’s written in a conversational style it’s also broad enough to form several wider interpretations.
See for example the following from Pope St John Paul II’s Familiaris Consortio paragraph 84, which explicitly and in all cases refuses Communion to those Catholics who engage in sexually activity outside of a valid marriage for several reasons as explained in the text. Some are suggesting that this has changed with AL, but no explanation is ever given to demonstrate how such an interpretation wouldn’t be a contradiction of past teaching, or explain away why the reasons previously given are no longer relevant.
However, the Church reaffirms her practice, which is based upon Sacred Scripture, of not admitting to Eucharistic Communion divorced persons who have remarried. They are unable to be admitted thereto from the fact that their state and condition of life objectively contradict that union of love between Christ and the Church which is signified and effected by the Eucharist. Besides this, there is another special pastoral reason: if these people were admitted to the Eucharist, the faithful would be led into error and confusion regarding the Church’s teaching about the indissolubility of marriage.
Reconciliation in the sacrament of Penance which would open the way to the Eucharist, can only be granted to those who, repenting of having broken the sign of the Covenant and of fidelity to Christ, are sincerely ready to undertake a way of life that is no longer in contradiction to the indissolubility of marriage. This means, in practice, that when, for serious reasons, such as for example the children’s upbringing, a man and a woman cannot satisfy the obligation to separate, they “take on themselves the duty to live in complete continence, that is, by abstinence from the acts proper to married couples.”
There is also comparison to the teaching in the 1994 letter of the Congregation for the Doctrine of the Faith on the specific subject:
Two Catholic theologians, Germain Grisez and John Finnis, have also issued a document outlining several different divergent/contradictory interpretations of AL which can be formed from the text, and have asked the Pope to condemn misuses of his document: