This is about the 200th anniversary of the claimed "FIRST" vision. But since there are so many versions and they can't pin down the year, they have broadened it to the next FEW years, 1817-182?. (Read the Apologetic Literature)
If the Church was to celebrate it in 2020, that might mean that they are advocating that date for the vision, and you know how they are at being evasive with something that they won't make "official". So this is basically them saying there is NO "OFFICIAL" stamp on the year of the claimed "first" vision.
Notice in the recent anonymous essay which has an "official" stamp, there is no specific declaration that it took place in 1820 and they throw out a lot of dates in it:
https://www.lds.org/topics/first-vision ... g&old=trueDocumentary evidence, however, supports Joseph Smith’s statements regarding the revivals. The region where he lived became famous for its religious fervor and was unquestionably one of the hotbeds of religious revivals. Historians refer to the region as “the burned-over district” because preachers wore out the land holding camp revivals and seeking converts during the early 1800s.6 In June 1818, for example, a Methodist camp meeting took place in Palmyra, and the following summer, Methodists assembled again at Vienna (now Phelps), New York, 15 miles from the Smith family farm. The journals of an itinerant Methodist preacher document much religious excitement in Joseph’s geographic area in 1819 and 1820. They report that Reverend George Lane, a revivalist Methodist minister, was in that region in both years, speaking “on Gods method in bringing about Reformations.”7 This historical evidence is consistent with Joseph’s description. He said that the unusual religious excitement in his district or region “commenced with the Methodists.” Indeed, Joseph stated that he became “somewhat partial” to Methodism.8
We do though, know the date of Joseph's first arrest for glass-looking, (and have the actual evidence) and that is 1826.
Also, when he borrowed, (and afterwards stole) the peepstone he used to "translate" the Book of Mormon: 1822.
https://user.xmission.com/~research/central/resth9.htm