According to the FTA, new requirements became apparent during the pilot phase for the implementation of the new cross-border commuter agreement of 23 December 2020 between Switzerland and Italy, which must be implemented retroactively in order to meet the requirements of the agreement. Part of this is also the specification of the Wage Standard CH (ELM) and thus the implementation in the ELMVersion 5.0 certified ERP systems.
Further information is available from the withholding tax departments of the cantons of Graubünden, Ticino and Valais and here.