Python 2 was deprecated when Python 3 was released, but the timeline of transition was over 10+ years.
Django has deprecation timelines that last over 1.5 years.
In Enterprise, its often seen to have deprecation last 7 years.
During deprecation, only maintenance is performed. That is---security fixes.
The real difference between deprecation and "maintenance mode" is that the later is indefinite and implies continuation until profit-loss. AWSv2 isn't in maintenance mode, its deprecated. Eventually Amazon may stop offering it, and doesn't want you to start using it, but while its in operation that doesn't mean they won't close security holes in services that offer it.
(Submitted title was "Google deprecating Angular 1.x Material library and is just closing issues and PRs", which was wrongly editorialized, since the article apparently doesn't say they're 'deprecating' the library, and 'just' is just spin. Submitters: please don't rewrite titles to put your spin on a topic, especially not to gin up controversy. If a title is misleading or linkbait, it's ok to rewrite it (see the HN guidelines), but the new title needs to be accurate and neutral, and should preferably use representative language from the article itself.)
Not sure if that helps that much though.