From The Watchtower, June 1, 1967, page 331, para 7:
Some have called Jehovah’s witnesses “false prophets” because, in times past, they have viewed things a certain way and, later, have made a change through their official publications. Or, there may have been practices by some members in the organization that have been permitted to continue for a time for lack of knowledge as to how to handle these things, but later they have learned from God’s Word what his will is and have gone ahead and made the necessary corrections. False prophets do not correct themselves. God’s people do.
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The following is a comment on these words by Alan Rogerson in his book: “Millions Now Living Will Never Die: A Study of Jehovah’s Witnesses”, pages 82-83 (Constable, 1969):
The above explanations are clearly preferable to the previous Society line that they had always been right. Nevertheless the Society is still not telling the whole truth. They do not say that up to now they have not admitted their mistakes, no wonder they were called 'false prophets'. They are also very coy about how much they confess; my impression is that they only admit to errors that are blatant and liable to cause individual Witnesses to fall away; if possible they sweep most of their past errors under the carpet of soothing historical generalisations. It is typical of the Society to use even their errors as evidence that they are right: 'False prophets do not correct themselves'. They are making a virtue out of their repentance, forgetting about the fact that they were wrong! Of course it is better to repent of error than not to repent, but I should have thought it was more typical of God's·organisation not to make errors at all. The Witnesses' reply to this is that human beings are fallible and even those in God's organisation are not immune from error. It seems to me, however, that this makes it difficult to decide which is God's organisation if that too is prone to error, and the New World Society has made so many errors in the past that they do not appear to be the likely candidates.