Hi TK, the code of canon law was updated in 1983.
Where there once was a hardline against “Protestant heresies”, Vatican II brought in the spirit of ecumenism, which is reflected in the 1983 code.
Can. 751 Heresy is the obstinate denial or obstinate doubt after the reception of baptism of some truth which is to be believed by divine and Catholic faith; apostasy is the total repudiation of the Christian faith; schism is the refusal of submission to the Supreme Pontiff or of communion with the members of the Church subject to him.
Can. 752 Although not an assent of faith, a religious submission of the intellect and will must be given to a doctrine which the Supreme Pontiff or the college of bishops declares concerning faith or morals when they exercise the authentic magisterium, even if they do not intend to proclaim it by definitive act; therefore, the Christian faithful are to take care to avoid those things which do not agree with it.
Can. 753 Although the bishops who are in communion with the head and members of the college, whether individually or joined together in conferences of bishops or in particular councils, do not possess infallibility in teaching, they are authentic teachers and instructors of the faith for the Christian faithful entrusted to their care; the Christian faithful are bound to adhere with religious submission of mind to the authentic magisterium of their bishops.
Can. 754 All the Christian faithful are obliged to observe the constitutions and decrees which the legitimate authority of the Church issues in order to propose doctrine and to proscribe erroneous opinions, particularly those which the Roman Pontiff or the college of bishops puts forth.
Can. 755 1. It is above all for the entire college of bishops and the Apostolic See to foster and direct among Catholics the ecumenical movement whose purpose is the restoration among all Christians of the unity which the Church is bound to promote by the will of Christ.
- It is likewise for the bishops and, according to the norm of law, the conferences of bishops to promote this same unity and to impart practical norms according to the various needs and opportunities of the circumstances; they are to be attentive to the prescripts issued by the supreme authority of the Church.
You can then turn to the Vatican II Council, particularly Nostra Aetate:
Likewise, other religions found everywhere try to counter the restlessness of the human heart, each in its own manner, by proposing “ways,” comprising teachings, rules of life, and sacred rites. The Catholic Church rejects nothing that is true and holy in these religions. She regards with sincere reverence those ways of conduct and of life, those precepts and teachings which, though differing in many aspects from the ones she holds and sets forth, nonetheless often reflect a ray of that Truth which enlightens all men. Indeed, she proclaims, and ever must proclaim Christ “the way, the truth, and the life” (John 14:6), in whom men may find the fullness of religious life, in whom God has reconciled all things to Himself.
The Church, therefore, exhorts her sons, that through dialogue and collaboration with the followers of other religions, carried out with prudence and love and in witness to the Christian faith and life, they recognize, preserve and promote the good things, spiritual and moral, as well as the socio-cultural values found among these men.
Thanks Marie.