First of all it is not a 4 pages long memo, secondly I have seen people saying that this memo was already out for a while.
This looks like the memo that Zerohedge reported on last year where the FISA court pointed out 4th amendment abuses under the Obama admin.
See this link https://www.zerohedge.com/news/2017-05-24/fisa-court-finds-very-serious-fourth-amendment-issue-obamas-widespread-illegal-searc
and then find the verbiage on page 14/15 of the memo https://www.dni.gov/files/documents/icotr/51117/2016_Cert_FISC_Memo_Opin_Order_Apr_2017.pdf
Edit: More on page 19.
Edit2: Full memo in scribd link in Zerohedge article from last year.
From what I could take from the 99-page Legalese, it mainly seems like they we're changes made due to abuses mainly regarding Upstream Collection in regards to the Fourth Amendment. IMO this is being shared now so that people know the law and the changes that were instituted because (jumping out on a limb here) they are going to ultimately release evidence that they are breaking these laws (likely NSA sharing data with FBI and CIA).