Partially updates the general settings and contact info of the customer identified by {customerId}. {customerId} must match the customer resolved from the bearer token; a token scoped to a different customer gets 403, even if that customer would otherwise be reachable through a reseller/MTS relationship. Requires the Settings permission and DoiT API access (platform:externalApi); updating allowedInviteDomains additionally requires the UsersManager permission.

The request body must use application/merge-patch+json (RFC 7396): an omitted field leaves the current value unchanged, and an explicit null also leaves it unchanged, except for urlSlug, where an explicit empty string removes the customer's active URL slug rather than leaving it unchanged.

Fields are nested exactly as getCustomer returns them - currency and allowedInviteDomains under settings, emails under contact - so every value is read and written at the same path. settings.currency accepts only the codes listed in the schema and cannot be cleared; allowedInviteDomains and contact.emails are cleared with an empty array.