What is the difference between each version of the Android SDK and the new version of the SDK api? Why can Backwards compatibility be said?

  android, question

What is the difference between each version of the Android SDK and the new version of the SDK api? Why can Backwards compatibility be said?

Of course, the later, the more new functions there are, for example:

Android 10(2.2.3/2.2.4) and the following versions have no fragment, starting from 11(3.0.x). This is the new feature, and there are many more.

I don’t understand what the topic “Backwards compatibility” specifically refers to, as far as I understand it:

In order to enable the old version of sdk to use the features and functions of the new version, the government will give additional jar packages, or take fragment as an example. What if the app I develop must be able to run on the 2.3 system, but at the same time, what if I want to use fragment? At this time, the android.support.v4.jar package can be used, which is the official compatibility solution.

It can be found that with the continuous upgrade of SDK versions, more and more jar packages are officially provided, android.support.v7.jar,v13 ……

If you want to know more about the new features brought by the upgrade of some versions, please visitAndroid 5.0 Behavior Changes, of course, if you are interested, you can also find version history’s upgrade record, not to mention here. . .