Mainframe retirement
IBM mainframe out, x64 in. Up to 28 specialists on the project, a mix of external experts and the customer's own people. A mainframe is business-critical by definition — there is no trial run at half load.
The actual work: prying the COBOL applications and DB2/z structures out of the legacy system. Analyze, extract, rebuild. Plus a new development pipeline so the applications would not only run after the move but could keep evolving.
The target architecture came out of that mix: Micro Focus COBOL Enterprise Server specialists, Oracle people, DB2/z architects. The customer ran the migration themselves. We built the road and kept a hand on it.