Every decommission checklist ranked for this query already has the bullet: map every upstream and downstream system, integration and report before you turn anything off. None of them say how, and how is the entire difficulty; a list built by asking a team what still connects is a list of what people remember. Even a well-built one caps its own verification short: one widely used decommissioning template recommends monitoring for 24 to 48 hours after cutover, which never touches a dependency that only runs once a month.
On the worked example already in the sheets, a 180-day connection log pull for Averill Mutual Insurance's retired PolicyCore system found 19 live connections against 13 the existing integration inventory named. Of the 6 nobody had listed, 4 were already dead and 2 were live: a commission dashboard reading the database directly, and a nightly job feeding a table a quarterly reinsurance report depends on, one hop removed. Cross-referencing the report catalog separately found that same reinsurance report; the connection logs alone never would have, because the report itself never queries PolicyCore.
This space starts once a replacement is already live and handling real transactions, not before. Picking or building that replacement is a separate CRM implementation job, and validating the one-time data cutover itself is what a systems migration plan covers. What is left, finding every connection and report nobody remembered before anything gets deleted, and sequencing the shutdown around what that check actually found, is what this pack tracks to close.