New versions, rehearsed first
Upgrades are where most ERP projects get hurt: a new version breaks a customization, or a report changes its numbers.
We rehearse every upgrade on a copy of your system, check your reports and your drafts' log before and after, and only then upgrade the real one. Customizations are built as separate add-ons, never as changes to the core, so they survive upgrades.
Included in Enterprise (for the enterprise components) and the Hosted service (everything).