发送消息时环信账号是否区分大小写?

通过

- (EMConversation *)getConversation:(NSString *)aConversationId

                               type:(EMConversationType)aType

                   createIfNotExist:(BOOL)aIfCreate

方法获取EMConversation对象,传入的aConversationId为D_123,结果返回的对象EMConversation的conversationId为d_123,
然后发送消息时构建EMMessage

- (id)initWithConversationID:(NSString *)aConversationId

                        from:(NSString *)aFrom

                          to:(NSString *)aTo

                        body:(EMMessageBody *)aBody

                         ext:(NSDictionary *)aExt

传入的aConversationId和aTo都是d_123(对方注册的环信账号时D_123),但是对方可以正常收到消息
求解释???????