Rails upgrade companies

I'm wondering if anyone has any experience with any of the Rails upgrade companies that are out there? We're looking to get all of our apps on the latest and greatest and trying to decide if hiring one of these companies would be better than us upgrading them ourselves.

https://www.fastruby.io/
https://www.bacancytechnology.com/landing/ruby-on-rails-4
https://railsfactory.com/rails-upgrade
https://www.upgraderails.com/

Difficult choice indeed. Ready to discuss this in public? What parts do you consider in the decision?

Hi everyone, just sharing my two cents after doing some research:

One firm to consider is Capital Numbers (https://www.capitalnumbers.com/ror.php) . They present themselves as an in-house team (no freelancers), offer Rails development, migration, support & optimization, and claim to have ISO 9001 & 27001 certifications. Their pricing is flexible (time & material, dedicated resource, etc.).

That said, I haven’t found any public upgrade case studies (Rails v-to-v) from them yet. Before signing on, I’d ask them for:

1) Past Rails upgrade examples (with challenges, before/after)
2) How they’ll handle merge conflicts with your dev branch
3) What they do if parts of your app are untested or brittle
4) Their plan for rollback, QA, and post-upgrade support

Personally, if your app is complex or has legacy parts, having a solid external team helps — but only if they deeply understand your code. If your internal team has enough Rails experience and bandwidth, doing it yourselves might give you more control. Either way, vendor or DIY, strict oversight and staging everything piecewise is key.

Anybody here used Capital Numbers for Rails upgrades (especially major version upgrades)? Would love to hear how smoothly (or bumpy) it went.