1. 安卓 1.0：
Android 1.0 是 Google 推出的第一个 Android 版本。它有一些基本功能，包括网络浏览器支持、相机支持、Gmail 帐户、谷歌地图和 Youtube 应用程序。虽然它没有像进一步介绍版本那样的正式版本名称，但非正式地称为Apple Pie 。 Android 1.0 版本的 API 级别为 1。在移动设备中不再使用它。它于2008年9月23日发布。
2. 安卓 5.1：
Android 5.1 是继 Google 推出的 Android 5.0.2 之后的下一个 Android 版本。它具有以前版本的所有功能，并且在此版本中添加了一些新的用户功能。此版本添加了多张 SIM 卡支持、用于加入 Wi-Fi 网络或控制蓝牙设备的快速设置快捷方式、丢失或被盗时的锁定保护以及高清语音通话等关键用户功能。在这个版本中完成了稳定性和性能增强。它的版本名称是Lollipop 。 Android 5.1 中的 API 级别为 22。它于 2015 年 3 月 9 日发布。
Android 1.0 和 Android 5.1 的区别：
| S.No. | ANDROID 1.0 | ANDROID 5.1 |
|---|---|---|
| 1. | It is the first version of Android. | It is the next version of Android after Android 5.0.2. |
| 2. | It is predecessor to Android 1.1. | It is predecessor to Android 5.1.1 and successor to Android 5.0.2. |
| 3. | It was released on 23 September 2008. | It was released on 09 March 2015. |
| 4. | The API level in Android 1.0 version is 1. | The API level in Android 5.1 version is 22. |
| 5. | It has 0 % android market share. | It has 11.5 % android market share. |
| 6. | It does not have official version name. | It has official version name like its other previous versions. |
| 7. | It has unofficial version name ‘Apple Pie’. | It has official version name ‘Lollipop’. |
| 8. | It had limited basic features like google maps, gmail, web browser, camera and youtube. | It had all features of previous versions and some new user features were added in this version. |
| 9. | It had single SIM card support. | Multiple SIM cards support was added in this version. |
| 10. | It had poor performance and less stability. | Stability and performance was enhanced in this version. |
| 11. | It had standard voice call. | High definition voice call was introduced in this version. |