In a Tikkun Atzum v'Nora, the GR"A stipulated to his Talmidim the count t(n)= 5500 + 35.750*n, replacing, as it were, the count to 5789 by a count to 5786. This unites the two messianic lines, in 5786, and prevents the death of Moshiach ben Yosef, in 5789.
The awesome result is that the birth that was to be in 5790, becomes two births, one of Moshiach ben Yosef in 5775/5776, and one of Moshiach ben David in 5786. The count to 5789 is not abolished. The Tikkunim stay as spiritual events, only the surface events have been changed.
This is the true middle path, between B'Ita and Achishena, B'Ita Achishena.
קומה ה' למנוחתי, אתה וארון עזך
קח נא אל את ברכתי, והחזק מגן חוזך