New International Version. We know also that the Son of God has come and has given us understanding, so that we may know him who is true.

And we know that the Son of God has come and has given us understanding, so that we may know him who is true; and we are in him who is true, in his.

20And we know that the Son of God has come and has given us understanding, so that we may know Him who is true; and we are in Him who is true— in His Son Jesus ...

We know that the Son of God has come and has given us understanding so that we know the real God. We are in the one who is real, his Son Jesus Christ.

And we know that the Son of God has come and has given us understanding, so that we may know him who is true; and we are in him who is true, ...

1 John 5:20 We know also that the Son of God has come and has given us understanding, so that we may know him who is true. And we are in him who is true by ...

The Son of God has come and has given us understanding, so that we may know him who is true; and we are in him who is true, in his Son Jesus Christ.

We are in him who is true by being in his Son Jesus Christ. He is the true God and eternal life. NIV: New International Version

The “true God” of 1 John 5:20 is the heavenly Father, and there is no precedent for believing that it refers to the Son.