::In most AX 2012 ā D365 F&O upgrades, the Tier 1 partner typically owns project governance, licensing, core implementation, data migration, and overall delivery, while the Tier 2/ISV partner focuses on their specific solution, customizations, integrations, and testing support.
Success usually depends on clear ownership, regular design reviews, and well-defined testing responsibilities. I’ve seen projects work well when the Tier 1 partner owns the platform and the ISV partner owns everything related to their solution footprint.