I'm constantly amazed at how few people have even heard about Letter VII. This includes well-seasoned Church leaders (Mission Presidents, Temple Presidents, Relief Society Presidents at all levels, etc.). Even fewer have read it.
This is all the more surprising because Joseph Smith made every effort to make sure the Saints knew about it. It was published in three Church newspapers (Kirtland, Nauvoo, and Philadelphia), as well as in a special pamphlet published in Liverpool. He had his scribes copy it into his journal so it would not be lost.
Here is the post where I encouraged people to ask their teachers about Letter VII.