Major release: A major release associated with an incremented first number (e.g. 9 or 10 [or DC for the current release]) and an approximate 18 month product cycle. These are only available as separate purchases or upgrades.
Planned update: A scheduled update that includes functional improvements, new security updates, and previously released out of cycle update updates. For 9.x and later, these updates are often quarterly; however, security improvements have sometimes resulted in longer times between updates.
Out of cycle update: An unscheduled update targeted at security fixes. These contain few functional updates with the intention to limit impact. The installers are cumulative to the last planned update.
Optional update: An update targeted at a narrow set of functional fixes with limited impact. Adobe recommends that you apply these patches if you are seeing an impact by one of more of the functional fixes being delivered.
