Quotes from WT - PIMI JWs will show as evidence, that the WT has apologized AND was not wrong:
*** w76 7/15 p. 441 pars. 15-16 A Solid Basis for Confidence ***
15 But it is not advisable for us to set our sights on a certain date, neglecting everyday things we would ordinarily care for as Christians, such as things that we and our families really need. We may be forgetting that, when the “day” comes, it will not change the principle that Christians must at all times take care of all their responsibilities. If anyone has been disappointed through not following this line of thought, he should now concentrate on adjusting his viewpoint, seeing that it was not the word of God that failed or deceived him and brought disappointment, but that his own understanding was based on wrong premises.
16 However, say that you are one who counted heavily on a date, and, commendably, set your attention more strictly on the urgency of the times and the need of the people to hear. And say you now, temporarily, feel somewhat disappointed; are you really the loser? Are you really hurt? We believe you can say that you have gained and profited by taking this conscientious course. Also, you have been enabled to get a really mature, more reasonable viewpoint.—Eph. 5:1-17.
*** w80 3/15 pp. 17-18 pars. 5-6 Choosing the Best Way of Life ***Not false - only premature
5 In modern times such eagerness, commendable in itself, has led to attempts at setting dates for the desired liberation from the suffering and troubles that are the lot of persons throughout the earth. With the appearance of the book Life Everlasting—in Freedom of the Sons of God, and its comments as to how appropriate it would be for the millennial reign of Christ to parallel the seventh millennium of man’s existence, considerable expectation was aroused regarding the year 1975. There were statements made then, and thereafter, stressing that this was only a possibility. Unfortunately, however, along with such cautionary information, there were other statements published that implied that such realization of hopes by that year was more of a probability than a mere possibility. It is to be regretted that these latter statements apparently overshadowed the cautionary ones and contributed to a buildup of the expectation already initiated.
6 In its issue of July 15, 1976, The Watchtower, commenting on the inadvisability of setting our sights on a certain date, stated: “If anyone has been disappointed through not following this line of thought, he should now concentrate on adjusting his viewpoint, seeing that it was not the word of God that failed or deceived him and brought disappointment, but that his own understanding was based on wrong premises.” In saying “anyone,” The Watchtower included all disappointed ones of Jehovah’s Witnesses, hence including persons having to do with the publication of the information that contributed to the buildup of hopes centered on that date.
*** w97 9/1 p. 21 par. 11 Keep Jehovah’s Day Close in Mind ***
11 Ridiculers may well have mocked faithful Christians because these had as yet unrealized expectations. Shortly before Jesus died, his disciples “were imagining that the kingdom of God was going to display itself instantly.” Then, after his resurrection they asked whether the Kingdom would be set up right away. Also, about ten years before Peter wrote his second letter, some were “excited” by “a verbal message” or “a letter,” reputedly from the apostle Paul or his companions, “to the effect that the day of Jehovah is here.” (Luke 19:11; 2 Thessalonians 2:2; Acts 1:6) Such expectations of Jesus’ disciples, however, were not false, only premature. Jehovah’s day would come!