backwardly

基本解释

First of all it explains what compatibility is and advocates small, incremental, backwardly compatible changes, while always focusing on future evolution.
书中并没有一味关注在未来的进步上，而是先解释了什么是小的、递增、后退的兼容改动，也解释了什么是造成这类改动的原因。
While most 2.0-compatible drives are backwardly compatible with 1.1, it is generally advisable to avoid using 1.1 unless there is no other option (due to its slow speed).
虽然大多数兼容 2.0 的驱动器都可向后兼容 1.1，但是一般最好避免使用 1.1，除非别无选择（因为它的速度比较慢）。
Both bundles as a whole and packages individually can be versioned, and increases in the minor number are used to signify new features (but remaining backwardly compatible).
两个bundle整体及各个包都可以有版本，增大minor号通常意味着增加了新特性（但保持向后兼容）。

The new USB 3.0 bus-powered portable hard drive is backwardly compatible with USB 2.0 ports, ensuring that all of the user's content is completely accessible.
ENGADGET: Verbatim's USB 3.0 Store 'n' Go external drives play nice with magnets, your data