Linnworks Royal Mail integration does not show the new service codes SU1, SU2, UNA/UNB, UNG/UNH in the available service drop-down menu.
The change from CRL service code to SU1 is only required for customers printing and manifesting directly with Royal Mail, not via 3rd party integrations. Same applies to the change from PPF, PK9 and PK0 services codes to SU2. In Linnworks, you can continue using old service codes (CRL, PPF, etc.).
Service codes UNA/UNB and UNG/UNH will not be made available by Royal Mail for any 3rd parties at all. In Linnworks, you will need to use STL and BPL service (codes) instead. This will allow existing shipping processes to continue without interruption, despite the implementation of these new codes by Royal Mail.