Guidewire Migration and Upgrade

Overview

Move a Guidewire deployment without losing policies, claims, integrations, or trust. Two related but distinct workflows:

Migration: on-prem InsuranceSuite → Guidewire Cloud (or one cloud tenant → another). Different infrastructure, different config-layer assumptions, different API surfaces.
Upgrade: in-place version bump (e.g., release 202403 → 202503). Same infrastructure, new code, new APIs, deprecated APIs to retire.

Both are heavy lifts that go badly if executed without rehearsal. Five production failures this skill prevents:

Config reconciliation gaps — on-prem carries 5 years of customizations; cloud tenant ships with newer base config; cutover deploys the on-prem config and breaks because base assumptions diverged.
Deprecated-API blind spots — version upgrade removes a Cloud API that an integration depended on; the integration starts returning 404 the moment the upgrade lands.
No mid-flight rollback — cutover starts at midnight, fails at 2am, decision is "abort or push through"; without a pre-defined abort path the team chooses badly.
Data migration that loses optimistic-locking history — claims migrate but checksum values do not; downstream integrations fail every PATCH for a week until checksums regenerate.
Communication misalignment — brokers told "use the new system Monday" while the old system is still authoritative for in-flight quotes; bound state lives in two systems.