We update the wiki with O/S each time we get an update and we have the previous O/S listing with when it was increased but we don't have any kind of progression as to when it increased each time.
Then, click on the view history tab (upper-right). You'll then see a list of edits that were made, you can compare the selected version to the prior version by clicking the "prev" link for the comparison. This may be helpful to getting some history on when the o/s changes were identified.
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