Migration SharePoint 2013 to SharePoint Online

In January 2023, I handled a project for SharePoint 2013 on premise to SharePoint Online {Microsoft 365}.
Scope:

  1. Document migration
  2. Custom Application for SharePoint 2013
    • UI inside some Master Pages
    • Solution .wsp
    • WebPart
    • Application Page
    • User mapping
  3. UI for SharePoint Online
  4. Custom Application - non SharePoint
    • The client had a lot of custom applications {non SharePoint}. All of them were integrated with SharePoint 2013 FBA - Form Based Authentication
    • todo: integrate authentication with Microsoft 365

1. Document Migration

The client stored documents in SharePoint 2013 on premise. Total document size was quite large {by 2023 standards}. They wanted to migrate all documents to SharePoint Online {Microsoft 365}.

2. Custom Application for SharePoint 2013

I divided the custom applications into 2 main groups:

  • Farm solutions
    • .wsp files containing .dll files, WebPart, Application Page
  • Non farm solution
    • UI using Master Pages
    • Script Editor Web Part

None of the applications had:

  • Custom Field
  • Custom Content Type
  • Custom Event Receiver

3. UI for SharePoint Online

Challenge:

  • Microsoft provided no sample or guideline on how to customize the UI for SharePoint Online.
  • SharePoint Online has no concept of Master Page

Solution:

4. Custom Application - non SharePoint

Challenge:

  • A lot of custom applications {non SharePoint}
  • Several vendors owned those custom applications:
    • I needed to coordinate with them
    • regarding application details and patching schedule

Action:

  • one by one, each application was patched at the authentication layer
  • PHP-based applications
  • ASP.NET Web Form applications
  • AngularJS FrontEnd applications

Technically, each application was patched as follows:

  1. patch Authentication on the FrontEnd side only
  2. patch Authentication on the BackEnd side