This was a complex scenario that required a number of different approaches.
Our first activity was to fully understand the position which was achieved by completing an architectural review of the overall solution, including integrated services.
Once we identified the issues and opportunities for improvement, we completed a migration plan with transition phases and releases. Due to the scale of the work, the larger programme of work was undertaken using a hybrid waterfall/agile project while the smaller tactical work was completed under a series of service management improvements. The work was completed while maintaining a high level of service for the customer and users.