Religion should adapt with modern changes. Past traditions which may be useful once upon a time, may no longer be relevant today.
There is difference between religion and tradition.
Traditions are ways of life to help adapt to time. Religion shelf life was meant to stretch for the life span of human beings.
I believe that if religion is to be adaptive, it can no longer be considered a religion. Is Confucianism a religion? And, if you really dissect it, is Buddhism really a religion even?
When a religion was formed, and 2000 years later they are still being practiced, there has got to be more to it than just a set of philosophies or traditions strung together.
Religion has its purpose:
1) It unites the people who follows it. One faith, one mind, one direction, one family.
2) It guides life through a set of values and laws for its people to be the best they can possibly be.
Also, I believe that if religion is to adapt then it will be a set of individual philosophies whereby no one true form is correct. I can always say that Muhammad's teachings of the Koran or Jesus' teaching of the Bible is relevant then but not now. I take what I want to take, practice what I want to practice, and leave out what I don't want. If religion can be so easily adapted, I can say that God exist but He is irrelevant now.
Heck, I can even say MORALITY is irrelevant, seeing how morality stems from religion.
If I were to adapt an "adapt to modern changes" approach, I WILL steal, rape, fight and murder, as and when I feel justified to do so. My excuse? "I am acting on my primal instincts of a human being", "Conformity is the new religion, and thus I am escaping from that religion that I do not wish to follow" or "If society can adapt to the changes of mindset, then society can accept the changes of MY mindset".
We will live by our own rules, with nothing to clearly define us as human beings. Religion may seem backwards to us now. But if we were to let everyone follow their own adaptive thinking of life, we will eventually be more backdated than the religion itself. Everybody will have their own answer, with no standards to live, and thus it becomes a modern stone age way of living.