Special Characters in Costing value sets

Summary:

For Project and activities in the third party system accounting system that a client has , there are special characters which are present in the datasets.

Since these are valid in the Third Party Accounting system which Client has, we would like to get the following queries clarified.

1) What characters are acceptable in the Costing value sets - that will not lead to any downstream impact, including costing process

2) If any of the above character is not acceptable and the client fears that as there is no restriction on the CMIS Cyborg legacy source (Accounting system for the client) , if similar data is created, there can be a probability in future for these characters to reappear in incremental load.