NIC is happy to introduce eInvoice2 portal. It is second portal of NIC – IRP (National Informatics Centre – Invoice Registration Portal), this is in addition to the existing eInvoice1 portal. Eligible tax payers can register their invoices either on the eInvoice1 portal or on the eInvoice2 portal.

Note:
1. Once the user registration is done in eInvoice1 portal, the tax payer can use the same user credentials for both the portals and E Way Bill portal.
2. Credential changes like change of password, client secret (for direct API users), forgot user name & password etc. is enabled only at eInvoice1 portal. The same will be reflected at eInvoice2 within short time.
3. Generation of eInvoices on eInvoice 2 portal can be carried out independently.
4. All the operations such as get eInvoice details, cancel eInvoice and E Way Bill by IRN as reference should be carried out on the respective portals where the eInvoice is generated. i.e. if eInvoice is generated on eInvoice1 portal, get details, cancellation and E Way Bill generation referring to the IRN for that invoice has to be done only on eInvoice1 portal.
5. For users having direct access to APIs, only the base URL will change i.e. from api.einvoice1.gst.gov.in to api.einvoice2.gst.gov.in if they want to access eInvoice2 APIs. There is no need to request for whitelisting the IPs separately for eInvoice2 API system.

Source: GST E-invoice Portal
The Release Note on e-invoice 2 Portal can be accessed at https://einvoice2.gst.gov.in/Documents/einvoice2.pdf