QuickBooks Online (QBO) write to Custom Fields on Invoice via v2 IPP .NET SDK in C#

Question

There are three custom fields that can activated on QuickBooks Online's Invoice.
How do I write to these fields using the v2 IPP .NET SDK with C#?
I do not see any field in the header that could be used to write to these fields.

Answer 1

In V2 QBO, Custom fields are supported for Customer and Job entities only. Ref - https://developer.intuit.com/docs/0025_quickbooksapi/0058_faq/qbo_v2_to_v3_migration_guide#Custom_Fields#Custom_Fields

You can try V3 QBO REST APIs - https://developer.intuit.com/docs/0025_quickbooksapi/0050_data_services/020_key_concepts/0200_custom_fields

V3 .Net Devkit (Custom Fields API Ref) - https://developer.intuit.com/docs/0025_quickbooksapi/0055_devkits/0150_ipp_.net_devkit_3.0/custom_field_apis

Thanks