The Scandit team shares their Cassandra upgrade process from 0.6.x to latest 1.0.x:
After extensive testing, we found that it fit our needs and decided to use the 0.6.0 release for our first roll out. Over the next 12 months, we kept upgrading our cluster until we reached 0.6.13, which was the last release in the 0.6.x branch.
In the meantime, Cassandra was evolving at an amazing speed. Many cool new features, such as secondary indices, CQL and schema support were added. Since we were very happy with our deployment, we moved a little slower and skip the 0.7.x releases. Now that 1.0.x has been around for a few months, we decided it was time to upgrade. Because the list of changes between the two versions was fairly long, we did the upgrade in two steps: First from 0.6.13 to 0.8.7 and then from 0.8.7 to 1.0.8.
Original title and link: Cassandra: How to Upgrade an Early Cassandra Cluster - ( ©myNoSQL)