2.1 Eclair has reached the threshold of being less than 0.1% of the Android ecosystem, Google will stop supporting the Android Market on those systems. Of course, because those systems make up such a small percentage of the Android whole, it shouldn't matter much. Google introduced the Play Store with Android 2.2, so any devices older than that should probably upgrade anyway (given that they're about seven years old at this point.)The shocker may be that Google has been supporting the Android Market on older devices all this time, but that time has passed. Google has announced that because Android
Surprisingly, there are versions of the Android Market for Android 2.2 devices still active in the world, so Google will continue to support those systems, but theoretically those days are numbered and users with devices that old will be forced to upgrade to something that is newer than seven years old. That seems reasonable, doesn't it?
source: Android Developers