the NKJV, is it just an updated KJV translation?

Matthew 7:14

KJV: "Because strait is the gate, and narrow is the way, which leadeth unto life..." 

NKJV: "Because narrow is the gate and difficult is the way which leads to life," 

Is the way unto eternal life difficult? No, that is false teaching. The way unto eternal life is "strait," as the KJV says, meaning "constricted, restricted, distressed, narrow, restrained."

Matthew 20:20

KJV: "Then came to him the mother of Zebedee's children with her sons, worshipping him..."

NKJV: "Then the mother of Zebedee's sons came to Him with her sons, kneeling down..." 

This is a wicked change. To kneel is obviously not the same as worship. "Worship" was in Tyndale's translation of 1526. It was in the Matthew's Bible of 1537. It was the Geneva of 1537. It was in the Authorized Version of 1611. Even the English Revised version of 1881 and the American Standard Version of 1901 retained the word "worship." It was the modernistic Revised Standard Version of 1952 which changed to "kneeling." Now the NKJV editors follow this same wicked error.

I Corinthians 1:18

KJV: "... but unto us which are saved it is the power of God." 

NKJV: "... but to us who are being saved it is the power of God..."

This necessary change corrupts the doctrine of salvation and conforms to the heretics who teach that salvation is a process.

Philippians 2:6

KJV: "Who, being in the form of God, thought it not robbery to be equal with God." 

NKJV: "Who, being in the form of God, did not consider equality with God something to be grasped."

This unnecessary change conforms to the doctrine of heretics who teach that Christ was not God.

Hebrews 2:16

KJV: "For verily he took not on him the nature of angels; but he took on him the seed of Abraham." 

NKJV: "For indeed He does not give aid to angels, but He does give aid to the seed of Abraham."

This verse properly translated deals with the nature of Christ's incarnation, but the complete and unnecessary change in the NKJV renders it meaningless.

Hebrews 3:16

KJV: "For some, when they had heard did provoke: howbeit not all that came out of Egypt by Moses." 

NKJV: "For who having heard rebelled? Indeed, was it not all who came out of Egypt led by Moses?" 

The NKJV make this verse to say something directly contrary to the KJV and to the Old Testament. The Bible plainly says that not all of the Israelites rebelled against God, but the NKJV creates a contradiction.

Hebrews 10:14

KJV: "For by one offering he hath perfected for ever them that are sanctified." 

NKJV: "For by one offering He has perfected forever, those who are being sanctified."

This unnecessary change in the NKJV conforms to heretical gospels, such as that taught by Rome, which claim that salvation is a sacramental process. The NKJV completely destroys the beauty and power of this verse, that through the once-for-all sacrifice of Jesus Christ the believer is perfected and sanctified forever. This verse properly translated, as in the KJV, defeats false views of salvation. The NKJV, on the other hand, creates confusion. If Christ's offering gives eternal perfection, as the first half of the verse claims, why does the rest of the verse say that we are BEING saved? It is confusion and error.