The Catholic Church does not believe in relativism when it comes to the truth. We claim that we have the truth entrusted by Jesus Christ to the apostles and are guardians of it. Hence, all of the Catholic teachings on faith and morals have not changed. Mind you, fath and morals have not changed, but disciplines or liturgy may have.
Now, is it right to boast and to brag to others that we have the truth. Absolutely not! In fact, it is rather counter productive. if we posess the truth, the most loving thing to do is to share it with others with charity and humility.
Now, does that mean that all who are non-Catholic are going to hell for rejecting the truth? No! Because one who is incapable of knowing the truth - whether through invincible ignorance or another impediment - cannot be held accountable for not believing it.
Does it also mean that we are right and everyone else is wrong? No! We claim that all of our teachings are 100% true, but elements of truth can be found elsewhere in other religions. It is the responsibility of us as Catholics to build on the commonality of different religions and share with them the elements that they are missing. If we do it just right, the Holy Spirit will lead them home.