Well, according to the Mormons, you can read all kinds of new stuff...
In the Bible it is written in Deuteronomy 4:2
Ye shall not add unto the word which I command you, neither shall ye diminish [ought] from it, that ye may keep the commandments of the LORD your God which I command you.
I would suggest that God would know when to call his book "done". The New Testament, is quite complete, and any new additions would be suspect just due to the finality of the existing work.