CD's > CDs

The -s is the plural, not the possessive, so no apostrophe is used here.

Thank you. It seems that CDs is gaining ground on CD's. The latter was never wrong; it depended on which style manual you consulted. In Wikipedia they use both in the same article.

" In 1983, in CD's introduction year, Immink and Braat presented the first experiments with erasable compact discs during the 73rd AES Convention.[29] In June 1985, the computer-readable CD-ROM (read-only memory) and, in 1990, CD-Recordable were introduced, also developed by both Sony and Philips.[30] Recordable CDs are an alternative to tape for recording music and copying music albums..."

CD's introduction year = the introduction year of CD(s)
I think that's a possessive apostrophe here.

Speaking of wrong, there is nothing wrong except that which nobody takes for granted, otherwise everything is merely disapproved of by some. :)

In any case, with CDs we are on the safe side. :)

Thank you both for your comments. With our online dictionaries, it reminds me of the novel 1984 where records can be changed obliterating all references to a past reality. Here is a site where a person who was also taught that the plural of acronyms are shown by apostrophe s.
http://english.stackexchange.co...strophe-or-not

(Apparently we still use apostrophes to show the plural of single letters: dot your i's and cross your t's.)