Errors while upgrading to fix pack
When you are upgrading to a fix pack, you must upgrade the DC1 nodes first followed by subsequent data centers. However, after you upgrade the Global Mailbox initial node on DC1, errors querying tables might occur.
When you upgrade the Global Mailbox initial node, a schema change occurs. After the initial node is upgraded, errors occur on the existing nodes that are not yet started while querying tables that have new columns. This is a known Cassandra limitation. To resolve this issue, see https://datastax-oss.atlassian.net/browse/JAVA-691.