One-time project - Mirth and HL7 interface

Looking for an experienced HL7 engineer for an short term HL7 project. Expert with Mirth. Project is to transform HL7 version 2.3 messages to HL7 version 2.5 You will be asked to answer the following questions when submitting a proposal: How many years of active HL7 and Mirth experience you have? What challenges you faced during HL7 mappings and transformations and how did you overcome those? What experience do you have with HL7 version 2.5? Explain 1 complex HL7 integration you worked on.