The variation would relate in particular to the conduct of the Earl of Oxford.
Slight as this reference is, there is yet enough in it to suggest another reason why Swift should withhold the publication of his work.

It might be that this expressed intention of Bolingbroke's to animadvert on his dear friend's conduct, would just move Swift to a final rejection of his intention, and so, possibly, prevent Bolingbroke from publishing his own statement.

However, the manuscript must have been returned, for nothing more was heard of it during Swift's lifetime.
Swift died in 1745, and thirteen years later appeared the anonymously edited "History of the Four Last Years." Is this the work which Swift wrote in 1713, which he permitted Pope and Bolingbroke to read in 1727, and which he prepared for publication in 1737?
In 1758 there was no doubt whatever raised, although there were at least two persons alive then--Lord Orrery and Dr.William King--who could easily have proved any forgery, had there been one.
The first suspicion cast on the work came from Dr.Johnson.Writing, in his life of Swift, of the published version, he remarks, "that it seemed by no means to correspond with the notions that I had formed of it from a conversation that I once heard between the Earl of Orrery and old Mr.
Lewis." In what particulars this want of correspondence was made evident Johnson does not say.

In any case, his suspicion cannot be received with much consideration, since the conversation he heard must have taken place at least twenty years before he wrote the poet's life, and his recollection of such a conversation must at least have been very hazy.
Johnson's opinion is further deprived of weight when we read what he wrote of the History in the "Idler," in 1759, the year after its publication, that "the history had perished had not a straggling transcript fallen into busy hands." If the straggling manuscript were worth anything, it must have had some claims to authenticity; and if it had, then Johnson's recollection of what he heard Orrery and Lewis say, twenty years or more after they had said it, goes for very little.
Sir Walter Scott concludes, from the fact that Swift sent the manuscript to Oxford and Lewis, that it was afterwards altered in accordance with Lewis's suggestions.

But a comparison of Lucas's text with Lewis's letter shows that nothing of the kind was done.
Lord Stanhope had "very great reason to doubt" the authenticity of the History, and considered it as "falsely ascribed to Swift." What this "very great reason" was, his lordship nowhere stated.
Macaulay, in a pencilled note in a copy of Orrery's "Remarks" (now in the British Museum) describes the History as "Wretched stuff; and I firmly believe not Swift's." But Macaulay could scarcely have had much ground for his note, since he took a description of Somers from the History, and embodied it in his own work as a specimen of what Somers's enemies said of him.