The latest Windows at the moment (for the public, not Insiders) is Redstone 2
In a nutshell:
Threshold 1 - July 2015
Threshold 2 - November 2015
Redstone 1 (Anniversary Update) - July 2016
Redstone 2 (Creators' Update) - April 2017
Redstone 3 (Fall Creators' Update) - Late 2017/Early 2018 (Plans might change)
Updated "Creative" to "Creators'" - thanks
@shmsnh
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