MIgrate data from Version 5 cluster to Version 7 cluster

We recently purchased new cluster in which we installed Vertica Version 7. We have an old cluster in Vertica Version 5.1 which we want to retire. 
What is the best way to move data across two cluster. Note that copy cluster will not work since they are different version. The way we can think of is to download data as text files and move across the system. Is there a effecient or faster way of doing this.