Certain characters, such as the vertical tab (hex 0B) and form feed (hex 0C) cannot be encoded in XML. When using these characters in the name or description of a K2-integrated SharePoint list or library, you may run into errors when you package and/or deploy the solution. K2 Package and Deployment uses XML to store package information and to map missing references. Characters that cannot be encoded in XML may result in empty lists and deployment errors.
Avoid using unencodable characters in the names, descriptions, fields, and values in a SharePoint list or library.
For more information on valid XML characters see https://www.w3.org/TR/xml/#charsets