Most changes to the data types in the input or output message are not backward compatible.
对输入或输出消息中的数据类型的大部分变更都不是向后兼容的。
Python V3.0 is not backward-compatible with earlier versions, and it appears that V2.6 is the version most commonly in use.
PythonV3.0并不能向后兼容之前的版本，而且V2.6是使用最为广泛的版本。
If existing users are affected then the change is not backward compatible, and a strategy will be needed to manage the impact of the change.
如果现有用户受到影响，则变更不向后兼容，将需要使用策略来管理变更的影响。
To figure out why they could go forward but not backward, Dr. Thornton and his colleagues looked closely again at the old and new receptors.
为了找出蛋白功能不能逆转的原因，桑顿博士和同事们又仔细的对比了新老两种受体。
For life goes not backward nor tarries with yesterday.
因为生命不会后退，也不会在昨日流连。
For life goes not backward nor tarries with yesterday.
因为生命是不倒行的，也不与昨日一同停留。
For life goes not backward nor tarries with yesterday.
因为岁月无法倒流，生命也不会伫足于昨日。
For life goes not backward nor tarries with yesterday.
因为生命不会后退，也不会逗留在昨日。
This methodology starts to encounter issues when a new version of an application requires a new version of a library that is not backward compatible.
当新版本应用程序需要的新版本库不向后兼容时，此方法就会遇到问题。
Even though V5.0 is still not released publicly, it is safe to say that it is completely different from its predecessor in that it is not backward-compatible.
尽管V5.0还没有公开发布，可以肯定地说它与先前的版本完全不同，因为它不是向后兼容的。
When the World Wide Web Consortium (W3C) released the first working draft of XHTML 2.0 on 5 August 2002, the major surprise was that, unlike its predecessors, it was not backward compatible.
当万维网联盟(WorldWideWeb Consortium (W3C))于2002年8月5日发布XHTML 2.0的第一个工作草案时，最让人吃惊的是：与其先前的版本不同，它不是向后兼容的。
Objects or attributes relating only to the new version will be lost after a backward migration, and therefore you should not backward migrate after running the new version for an extended period.
与新版本相关的对象和属性在向后迁移后将丢失，因此在运行新版本较长一段时间后最好不要进行向后迁移。
For life goes NOT backward NOR tarries with yesterday.
因为生命不会倒行，也不会滞留于往昔。
For life goes NOT backward NOR tarries with yesterday.
因为生命不会倒行，也不会滞留于往昔。
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