IBM BPM, V8.0.1, All platforms > Migrating and upgrading your IBM BPM environment > Migrating from previous versions
Mixed-version environments
Version-to-version migration of ND-based production environments frequently results in a period of time when the ND environment is running applications on different versions of IBM BPM. This concept is referred to as mixed versions.
Mixed versions of a product can theoretically be applied to multiple cells, mixed-version cells (multiple clusters or managed non-clustered nodes in a single cell), or mixed-version clusters (managed nodes in a single cluster). Only two of these types of mixed versions are supported by IBM BPM: multiple cells and mixed-version cells.
Multiple cells
If you have two cells that are initially at version 6.x or 7.x, one can be upgraded to V8.0.1 without having any administrative or database impact on the other cell. This is the simplest way to manage applications that are frequently running on different versions of IBM BPM.
Mixed-version cells
In addition to having cells at different versions, clusters and non-clustered managed nodes in a single cell can be at different versions.
For example, a cell might have one cluster at version 6.x or 7.x and another cluster that was at version 6.x or 7.x that has been migrated to V8.0.1. In a mixed-version cell environment, the cell-scoped Common database is being shared by all the clusters and non-clustered managed nodes that are running different versions of IBM BPM.
Mixed-version cell scenarios are not supported between version 6.x or 7.x and V8.0.1 when both are supporting applications that use the Business Calendars capability.
If, during the course of migrating IBM BPM to V8.0.1, your cell is running nodes concurrently at the new and premigration levels, be aware that when the dmgr has been migrated to the latest version, you cannot perform any of the following actions on nodes in the cell that are still at premigration levels:
- Configure Business Process Choreographer
- Install, update, or uninstall any applications that contain business processes, human tasks, or both
Mixed-version clusters
IBM BPM does not support nodes in a single cluster running on different versions of IBM BPM. This concept is referred to as a mixed-version cluster. If you have configured a cluster containing servers running different versions, all the members running earlier versions of the product must be stopped before you start the first V8.0.1 cluster member. Also, once the V8.0.1 cluster member is started, the members of the cluster configured at a pre-V8.0.1 level must not be started.
If, during the course of migrating to V8.0.1, your cell is running nodes concurrently at the new and premigration levels, be aware that when you have a cluster at the latest version that has Business Process Choreographer configured on it, you must not create any new cluster members on any nodes that are still at the premigration level.