bcquality/microsoft/knowledge/upgrade/first-install-dataversion-zero-check.md

bc-version	domain	keywords	technologies	countries	application-area
all	upgrade	dataversion first-install on-install-app-per-company moduleinfo zero-version	al	w1	all

Detect first install with DataVersion() = Version.Create('0.0.0.0')

Description

On the first install of an extension on a tenant the platform records a zero data version: AppInfo.DataVersion() returns Version.Create('0.0.0.0'). During reinstall, DataVersion() identifies the previously installed data version. The OnInstallAppPerCompany trigger uses this distinction to separate a brand-new install from a reinstall. Ordinary version upgrades do not run install code.

Best Practice

In OnInstallAppPerCompany, fetch the current ModuleInfo via NavApp.GetCurrentModuleInfo, compare AppInfo.DataVersion() to Version.Create('0.0.0.0'), and run first-install seed logic only when they match. On a non-zero data version, follow the reinstall path or exit.

See sample: first-install-dataversion-zero-check.good.al.

Anti Pattern

Treating OnInstallAppPerCompany as if it always implies "fresh tenant". The trigger also fires when reinstalling over an existing data set; without the 0.0.0.0 guard, first-install seed code can run again and duplicate rows.

See sample: first-install-dataversion-zero-check.bad.al.

See also

• use-upgrade-tags-not-version-checks.md — for upgrade steps after first install, use upgrade tags rather than DataVersion.
• install-code-does-not-run-on-version-upgrade.md — ordinary version upgrades invoke upgrade code, not install code.