According to Max Brod, Kafka gave the letter to his mother to deliver to his father but she never did.
[1] The original letter, 45 pages long, was typewritten by Kafka and corrected by hand.
[2] In 1954, the letter, translated into English by Ernst Kaiser and Eithne Wilkins, was published by Schocken Books in Dearest Father: Stories and Other Writings.
[4] A new translation by Hannah and Richard Stokes was published by Oneworld Classics in 2008 under the title Dearest Father.
Extracts from the letter, translated by Sophie Prombaum, are included in A Franz Kafka Miscellany.