Issue 1:
I have searched the issues of this repository and believe that this is not a duplicate.

I have checked the FAQ of this repository and believe that this is not a duplicate.

Environment

Dubbo version: 2.6.2 as consumer and 2.7.x as provider

Operating System version: mac os x

Java version: 1.8

Step to reproduce this issue

start basic provider with 2.7.x

start basic consumer with 2.6.2

Pls. provide [GitHub address] to reproduce this issue.

Expected Result

The invocation get right result.

Actual Result

What is actually happen?

If there is an exception, please attach the exception trace:

java.io.IOException: Unknown result flag, expect '0' '1' '2', get 4
at com.alibaba.dubbo.rpc.protocol.dubbo.DecodeableRpcResult.decode(DecodeableRpcResult.java:101)
at com.alibaba.dubbo.rpc.protocol.dubbo.DecodeableRpcResult.decode(DecodeableRpcResult.java:113)
at com.alibaba.dubbo.rpc.protocol.dubbo.DubboCodec.decodeBody(DubboCodec.java:89)
at com.alibaba.dubbo.remoting.exchange.codec.ExchangeCodec.decode(ExchangeCodec.java:124)
at com.alibaba.dubbo.remoting.exchange.codec.ExchangeCodec.decode(ExchangeCodec.java:84)
at com.alibaba.dubbo.rpc.protocol.dubbo.DubboCountCodec.decode(DubboCountCodec.java:46)
at com.alibaba.dubbo.remoting.transport.netty.NettyCodecAdapter$InternalDecoder.messageReceived(NettyCodecAdapter.java:133)
at org.jboss.netty.channel.SimpleChannelUpstreamHandler.handleUpstream(SimpleChannelUpstreamHandler.java:80)
at org.jboss.netty.channel.DefaultChannelPipeline.sendUpstream(DefaultChannelPipeline.java:564)
at org.jboss.netty.channel.DefaultChannelPipeline.sendUpstream(DefaultChannelPipeline.java:559)

Issue 2:
I have searched the issues of this repository and believe that this is not a duplicate.

I have checked the FAQ of this repository and believe that this is not a duplicate.

Environment

Dubbo version: 2.7.5

Operating System version: macos 10.15.13

Java version: 1.8

Steps to reproduce this issue

Spring boot 1.5.2 ,when update dubbo 2.5.3 to 2.7.5 ，I have some problems

run spring boot , and dubbo config is <dubbo:reference interface="com.xxx.xxx.service.ITaskService" version="${dubbo.api.version}" id="taskService" cluster="failfast"></dubbo:reference>

application.properties config is dubbo.api.version=1.2.0_dev

Actual Result

run error

the exception trace:

Caused by: java.lang.IllegalStateException: Invalid version="${dubbo.api.version}" contains illegal character, only digit, letter, '-', '_' or '.' is legal.
at org.apache.dubbo.config.utils.ConfigValidationUtils.checkProperty(ConfigValidationUtils.java:593)
at org.apache.dubbo.config.utils.ConfigValidationUtils.checkKey(ConfigValidationUtils.java:559)
at org.apache.dubbo.config.utils.ConfigValidationUtils.validateReferenceConfig(ConfigValidationUtils.java:340)
at org.apache.dubbo.config.ReferenceConfig.checkAndUpdateSubConfigs(ReferenceConfig.java:401)
at org.apache.dubbo.config.ReferenceConfig.init(ReferenceConfig.java:186)
at org.apache.dubbo.config.ReferenceConfig.get(ReferenceConfig.java:151)
at org.apache.dubbo.config.spring.ReferenceBean.getObject(ReferenceBean.java:68)
at org.springframework.beans.factory.support.FactoryBeanRegistrySupport.doGetObjectFromFactoryBean(FactoryBeanRegistrySupport.java:168)
... 64 common frames omitted