Acronyms (initials), numbers and dates
Apostrophes are NOT used in plurals of acronyms, numbers and dates, e.g.:
The 1960s (the decade of the Sixties). (But there is an initial apostrophe if 1960s is contracted to ’60s to show that the “19” is missing).
DVDs (a number of digital versatile discs)
However, apostrophes are used with acronyms and dates to show possession, e.g.:
The DVDs’ bright colours were a major selling point.
He recalled 1947’s exceptionally cold winter.