I don't get it...
The linked article says "On Monday, Apple issued a new installer that properly checks for available disk space."
That would be Monday, Feb.15th, but 11.2.1 was released on the 9th or 10th. (My receipt is dated the 10th.)
And Software update isn't offering me anything. ¯\_(ツ)_/¯
If your original installation did not have problems then you don't need to update anything. If I recall, the problem affected installations where there was not enough space for the installation process. Presumably the new installer now works correctly in this situation.
I installed 11.2.1 when and because Software Update offered it to me, and as I recall, it addressed a battery issue.
And anyway, your response doesn't address the date anomaly.
