While King James Version Bible is the oldest bible, it has been superseded by the KJV. In fact, some people would say that the modern version of the King James Bible is a compromise that has to be accepted as a translation from the original. One reason for this is that the Lectionary Bible (Book of Common Prayer) was very different than the King James version.
Before KJV was translated, the term Lectionary meant the Lectionary, the book of the Eucharist. During the time of the Lectionary, there were many churches that were starting their own translations of the Bible. The regular edition of the Bible was translated and put into the local church. They did not have the expensive printing costs of the larger editions.
The Lectionary was much less expensive to use and only needed one copy for every week of the year. Some churches used more than one copy and it was expensive, so they would often add more to the local edition of the Bible. So the KJV was somewhat lacking in many places, while there were plenty of other versions that were cheap and easy to use.
Today, the Lectionary Bible (Book of Common Prayer) has dropped out of use because it was not being widely used. Many people, especially those in large cities, do not have access to a Lectionary anymore. Instead, they go to the local church and go to Sunday school to get their lessons in the Lectionary.
Those who use the King James Version believe that the newer version is more faithful to the original. The King James version still allows for the use of the plural forms in some passages, but the translators have given consideration to the usage in the original text. The KJV, on the other hand, does not allow this.
On the subject of proper nouns, the KJV is much more precise. It is not necessary to use the singular form for pronouns, and people, places, and things are given the correct form for their singular and plural forms. The Lectionary is not as accurate because the plural form is not used in the book of Acts.
Another difference between the two is that there are misspellings of Biblical terms in the KJV. There are a few instances of common words that are misspelled or are capitalized incorrectly. While there are instances where people make a change for punctuation and spellings, this is not done consistently throughout the entire book.
When comparing the King James Bible and the KJV, it seems to be a more faithful version. It is accurate in the sense that the spelling and grammar of the Bible are consistent, though there are differences that should be taken into consideration.