Yes, the day the Sabbath is kept changed. The history of that is finally available to everyone, it is a long story.
After the crucifixion the Jews were the head of the church, their council decided about church policy. Many Jews felt that when the Messiah came He would get rid of the hated Romans, so when Christ didn't they decided He was not the Messiah. However thousands of Jews understood scripture to say that the Messiah would be a holy man, so they knew Christ was the Messiah. However, they wouldn't be able to understand the idea of God changing the day of the Sabbath.
There were terrible wars at that time. In the year 70 the temple was destroyed, many Christian Jews died at that time. In the year 132, the Romans made the Holocaust of Hitler look tame, many Jews were killed. Then the Christian gentiles took over the leadership of the Christian church. These people had always gone to their church on Sunday, or the day of the sun.
These gentile Christians were familiar with the idea of a God, they often simply Christianized how they worshipped. They made the way they had grown up into the way to worship the new God. Because it was Sunday that the women found that Christ had risen, they said it was right to change the worship day to Sunday. Scripture told them the day they chose wasn't the important thing.
It was only a little over 300 years AD that a council was called to decide if Christ was truly God. This council gave us the Nicene Creed many say to this day affirming Christ as God. These men also decided that Christians were to so separate themselves from anything Jews practiced that it was illegal to do such as have church on Saturday, or have a holiday talked of in the OT.
Scripture says that Christians who have the HS can do this, we can eliminate these things physically if we obey in spirit and truth. Because so much of the church is not doing any of these things in spirit and truth, there is a movement that started using the physical doing to be a reminder of the spiritual we are bound to do. Much of the established church is very upset over anyone obeying in this way, they are accused of only obeying physically for the wrong reasons.
According to scripture, Christians are not to use what day others worship on or how they celebrate to judge others. You are free to choose between the two days.