dataguard 版本必须一致吗？

昨天测试了一下Oracle 11.2.0.2 到 11.2.0.4的dataguard。
首先做duplicate database from active database是成功的。
然后用data guard broker去做，总是在备库报错 ORA-7445

后来考虑用手工方式，发现日志成功被传过去，并且apply也是成功的。
但能这么做生产用吗？

在itpub下面的文章中发现一段话：

在官方文档中终于找到答案了，phsical standby必须一致，logical standby可以不一致
As of Oracle Database 11g, and subject to current restrictions documented in MetaLink

note 4134841.1, Data Guard provides increased flexibility for Data Guard

configurations in which the primary and standby systems may have different CPU

architectures, operating systems (for example, Windows & Linux), operating system

Data Guard Operational Prerequisites

Getting Started with Data Guard 2-5

binaries (32-bit/64-bit), or Oracle database binaries (32-bit/64-bit). For specific

information about mixed-platform support, see Oracle MetaLink note 413484.1 at

https://metalink.oracle.com.

The same release of Oracle Database Enterprise Edition must be installed on the

primary database and all standby databases, except during rolling database upgrades

using logical standby databases.

这个note我尝试在metalink上打开，说是没权限。

看样子还是不要不同版本的好，万一出了什么错误就糟糕了。