The 8th chapter of Daniel discusses the Four Great Kingdoms that were to span history from the time of the fall of Bavel. It includes within it one of the well-known predictions in the book.
At the end, the question is asked: How long will it take for all this to transpire? The answer is terse enough:
He said to me: Until evening morning, two thousand, three hundred, and the holy one will be justified. (Daniel 8:14)
Among the commentators we see the opinion that the 2300 mentioned is 2300 years, see Rav Sa'adiah Gaon, Rashi, etc. The question, however, before looking to see what the end-date is, is to ask: what is the start date?
And the vision of the evening and the morning that was said, it is true; And you - hide the vision, for it is for many days. (Daniel 8:26)
Daniel indeed hid the true meaning of his vision, as he did later on in chapter 12, however in a different manner.
In the third year of the kingdom of Belshatzar the king, a vision appeared to me; me, Daniel, after what appeared to me at the beginning. And I saw in the vision, and it was when I was seeing, I was in Shushan... (Daniel 8:1-2)
The third year of Belshatzar was the last year of Belshatzar, and indeed the 70th year of the kingdom of Bavel, as brought in Megillah 11b. The Ibn Ezra takes note of this and states that it couldn't be that Daniel went to Shushan and came back even the same year. He saw himself in the future in Shushan.
Daniel is hinting to us that the starting point of the vision is in the future during the reign of Paras uMadai. The vision starts at the tachlit of their kingdom, the construction of the 2nd Beit HaMikdash, which came to fruition in 3408.
The year 3408 was a beginning that went awry. It would be a full cycle to start over.
And there was evening and there was morning, one day (Breishit 1:5)
It would be 2300 years to restart the cycle.
3408 + 2300 = 5708
Now, unlike then, we achieved the minimum threshold of ingathering, 600,000 souls. The Geulah is proceeding according to Daniel's vision, with the order of tefillah as its guide.