Our team is in the process of planning legacy ERP replacing project. Unfortunately it is quite custom, so the decision was taken to develop own one. Legacy system has a lot of inbound integrations (point of sales, backoffice) and outbound (finances, etc.)

While we do understand how to develop the system, it's quite hard to plan and estimate implementation, integration and deployment phase.

for example: It's very risky to plan go live just over weekend, since it's 24/7 business. Probably we need to have legacy and new systems working in parallel. If so, which one would inbound clients (e.g. mobile apps) connect ?

Does anyone have such kind of experience ? What approach should be used here ? I would be grateful for WBS example.

  • 1
    What are you asking? What do you want? Do you want someone to develop a WBS for your project? Would you place any credibility in a WBS developed blindly without any knowledge of your custom solution? Best practice is for the PM to develop the WBS in close cooperation with the staff who will actually do the work.
    – MCW
    Jan 8, 2016 at 13:57
  • It sounds like your a technical person, and the project does not have a professional Project Manager or Product Owner to guide the implementation. As such, this question is simply too broad for the Q&A format.
    – Todd A. Jacobs
    Jan 8, 2016 at 16:58
  • Honestly, this question is much too big for a forum. There are undoubtedly professionals in your city that specialize in big IT conversions and you need to engage their consultancy. Mar 19, 2020 at 15:59

1 Answer 1


Implementation of a custom ERP is a complex procedure. One should have experience to do it right. As I understand, you are a member of the development team and there is a customer enterprise.

If this is correct, you will need:

  • a roll-out engineer in the camp of development who knows how to extract information from an expert and teach the staff to use the system;
  • a roll-out team with special privileges on the customer’s side. The role of this team will be vital. They will be those people who work 24/7 being responsible for the result of the implementation.

We are writing a series of articles about development and rolling out ERP systems, so you may find some useful tips here: https://anadea.info/blog/erp-and-business-management-software-introduction.

Answering your question, you are right that most likely they will have to use two systems simultaneously until all workflows are fully transitioned to the new software. This is absolutely normal (albeit the staff doesn’t like it).


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