1.1.9 to 1.2.3 upgrade issue

[John Watson]

Started doing a rolling upgrade of nodes from 1.1.9 to 1.2.3 and nodes on
1.1.9 started flooding this error:

    Exception in thread Thread[RequestResponseStage:19496,5,main]
    java.io.IOError: java.io.EOFException
            at
org.apache.cassandra.service.AbstractRowResolver.preprocess(AbstractRowResolver.java:71)
            at
org.apache.cassandra.service.ReadCallback.response(ReadCallback.java:155)
            at
org.apache.cassandra.net.ResponseVerbHandler.doVerb(ResponseVerbHandler.java:45)
            at
org.apache.cassandra.net.MessageDeliveryTask.run(MessageDeliveryTask.java:59)
            at
java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
            at
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
            at java.lang.Thread.run(Thread.java:662)
    Caused by: java.io.EOFException
            at java.io.DataInputStream.readFully(DataInputStream.java:180)
            at
org.apache.cassandra.db.ReadResponseSerializer.deserialize(ReadResponse.java:100)
            at
org.apache.cassandra.db.ReadResponseSerializer.deserialize(ReadResponse.java:81)
            at
org.apache.cassandra.service.AbstractRowResolver.preprocess(AbstractRowResolver.java:64)
            ... 6 more

As I understand the Hints CF changed from 1.1.x to 1.2.x so I assume that's
the cause of the 1.2.3 nodes flooding (for various IPs still being 1.1.9):

    Unable to store hint for host with missing ID, /10.37.62.71 (old node?)

Is this a known issue? Or rolling upgrade form 1.1.x to 1.2.x not possible?

Thanks,

John