不过，如果虚拟设备供应商允许扩展，则必须提供在更新期间维护这些扩展的技术。

However, if the virtual appliance provider allows extensions, they must provide techniques to maintain these extensions during update.

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选项卡为水平的文件夹比选项卡为垂直的文件夹效果更好，因为它们允许扩展更长的选项卡名。

Wide horizontal tabbed folders work better than narrow vertical ones because they allow for greater expansion of tab names.

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一些工厂会有意识将架构固化，而另一些可能允许扩展(架构本身就是体现可变性的一个方面)。

Some factories will want to intentionally fix this architecture; some may allow it to be extended. (architecture can also be a point of variability).

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