Address
Utrecht, Veenendaal
Work Hours
Monday to Friday: 9am to 5pm
Weekend: 10am to 5pm
Address
Utrecht, Veenendaal
Work Hours
Monday to Friday: 9am to 5pm
Weekend: 10am to 5pm

The a.s.r. corporate platform moved off Sitecore and Vite onto headless Contentstack and Nuxt.js, over a track of more than a year, while it stayed up for visitors the whole way.
a.s.r. is one of the largest insurance companies in the Netherlands and its corporate platform is a working publishing operation, with editors in it every day. Replacing the CMS under that is not a technology swap. It changes how those people do their jobs, which is why the hard conversations were the valuable part.
Sitecore and Contentstack do not model content the same way, so a faithful one to one migration was never available. Some of what editors relied on could not be recreated in the same shape, and saying that out loud early, with a workable alternative beside it, was better than discovering it at go live. Meanwhile the site had to stay up: visitors, campaigns and search all carried on while the foundation under them was being replaced.
A replatforming is decided in the content model and the stakeholder conversations, and that is where I would start on yours.