why is Android API level 9 obsolete?

Question

Android version 2.3 - 2.3.2 (API 9) are declared as obsolete, and according to Android Market statistics, are very rare (0.5% of market users).

The question is: Why is API 9 declared obsolete and more importantly, is there any reason why should I not use it? I've been using API 9 and see no problems with it... am I missing something?

Better not fix it if it's not broken, right?

EDIT:

Clarification: If I would update my applications' API from 9 to 10, what would be the benefits?

I can only see negative effects: 1% of users will suddenly find out that the app doesn't work on their phones any longer. This is even worse with paid apps. Or that I'd be forced to maintain two versions of each app.

Answer 1

Have a look at the description of API levels. Gingerbread API (9) has been replaced by Gingerbread MR1 (10). You should upgrade to this API.