What This Update Actually Is
HubSpot released the Legacy CRM Card Migration Tool on April 24, 2026. It's a developer-facing API update, not a portal setting or an admin toggle.
Here's the core of what shipped: a new migrate views API endpoint. When an app developer calls it, HubSpot asynchronously updates every connected customer's CRM views. It hides the old Legacy CRM Card and surfaces the new App Card in its place.
The new App Cards are built with React and run on HubSpot's UI Extensions framework. That means dynamic content, richer interactivity, and a more flexible display layer compared to the old card format.
This update is scoped to app developers who have Legacy CRM Cards inside apps already on the Projects framework. If you're a business using HubSpot but not building apps, this one doesn't land in your lap directly. It lands in the lap of your app vendor.
Why HubSpot Shipped This
Legacy CRM Cards were the original way third-party apps embedded content inside HubSpot CRM records. They worked, but they were static, limited in layout, and couldn't keep up with what HubSpot's UI Extensions platform can now do.
HubSpot set an October 31, 2026 sunset date for Legacy CRM Cards. Without a migration tool, developers would have to coordinate with every customer to manually update their views. That's a coordination nightmare at scale.
The real internal frustration here: app developers were sitting on a ticking clock with no clean path forward. If they missed the deadline, their customers' CRM record views would break or go blank. No app developer wants that support ticket flood.
This tool gives developers a programmatic, customer-transparent path. One API call, one async update, zero disruption to the humans working inside those portals every day.
How to Use It Step by Step
HubSpot's documentation outlines a three-step process. Here's how it works in plain terms:
- Migrate your app to the Projects framework. Run hs app migrate in the HubSpot CLI. This moves your app and its existing Legacy CRM Cards into the Projects framework at the same time. You can't call the migrate views endpoint until this step is done.
- Build your replacement App Card. Create a new App Card using UI Extensions and dynamic React components. HubSpot provides example projects that replicate common Legacy CRM Card behaviors, so you don't have to start from scratch.
- Call the migrate views API endpoint. This triggers an async update across all connected customer portals. HubSpot hides the Legacy CRM Card and displays your new App Card. Customers see the new card on their next page load, no manual steps on their side.
The async nature of the endpoint matters. The swap doesn't happen instantly for every portal simultaneously, but it does happen without any customer-side action. Build your App Card first. Don't call the endpoint against a half-finished card.
What It Touches in Your HubSpot Strategy
This update is developer-side, but its ripple effects land squarely in the CRM record experience. Here's where you'll feel it.
CRM record views across any object (contacts, companies, deals, tickets) can contain App Cards. If your team relies on a third-party app that embeds data directly into those records, that card is almost certainly a Legacy CRM Card right now. After October 31, 2026, it could disappear.
Key Takeaway
If your team uses a third-party HubSpot app that shows data inside CRM records, contact your app vendor now. Ask them whether they've migrated their Legacy CRM Cards to App Cards. The October 31, 2026 deadline isn't negotiable.
For RevOps leaders and HubSpot admins, the action isn't technical. It's vendor management. Do an audit of every app installed in your portal that surfaces cards on records. Cross-reference against the developer's roadmap.
For developers building on HubSpot, this update intersects directly with how your app integrates into the CRM layer. The Projects framework and UI Extensions are now the only path forward. React-based App Cards open the door to richer interactivity: conditional displays, real-time data pulls, and more visual control than Legacy CRM Cards ever offered.
This change also connects to the broader pattern of HubSpot tightening up how CRM record views are configured. We covered a related shift in HubSpot's Sales Workspace update that replaced custom tabs with native CRM index pages. HubSpot is standardizing the record and workspace experience, and App Cards are the sanctioned way to extend it.
Key Takeaway
App Cards built on UI Extensions aren't just a replacement format. They're a capability upgrade. React-powered components let you build dynamic, context-aware displays that Legacy CRM Cards physically couldn't support.
If your portal's record views feel cluttered or broken after October 31, 2026, this migration is likely the reason. That's also why getting ahead of it now protects the productivity of every human on your team who lives inside those records.
Need a deeper read on keeping your HubSpot setup clean and purposeful? The 7 biggest HubSpot onboarding mistakes that cost companies thousands covers patterns we see repeatedly when portals drift from intention, including integrations that start breaking quietly before anyone notices.
Who Should Care Most
This update has two distinct audiences, and they need to take different actions.
- HubSpot app developers who built integrations with Legacy CRM Cards: you own the migration. Use the CLI, build the App Card, call the endpoint. Don't wait until Q3 2026.
- RevOps leaders and HubSpot admins at companies using third-party apps: audit your installed apps now. If a vendor's app shows cards on CRM records, email them today. Ask for their migration timeline.
- Sales and service operations teams whose reps rely on app data inside contact, deal, or ticket records: know that those cards could go blank in six months if nobody acts. Raise this with whoever manages your HubSpot portal.
- HubSpot Solutions Partners and agencies managing client portals: add a Legacy CRM Card audit to your portal health checklist. This is exactly the kind of quiet technical debt that surfaces as a client emergency in October.
George's Take
I've seen this pattern dozens of times across portals we audit: a third-party app is doing something useful inside a CRM record, but it's running on a foundation nobody's touched in two years. Everything looks fine until it doesn't. The Legacy CRM Card sunset is a defined deadline, and HubSpot actually did developers a favor here by shipping a migration tool that removes the customer-coordination headache. But the tool only helps if developers use it, and admins can only apply pressure if they know to ask. My honest take: most business owners and even most RevOps leads won't hear about this until a card goes missing. Don't be that story. Audit your integrations now, ask your vendors direct questions, and if you're a developer, the October 31 deadline has a way of arriving faster than it looks on a calendar.
“The migration tool removes the hard part. What's left is just doing the work before October 31. That's a choice, not a technical problem.”
If you want a fresh set of eyes on your portal before the sunset hits, or if you're a developer who needs a sounding board on the App Card build, let's talk. Book a HubSpot strategy call with the Sidekick team and we'll help you get ahead of this before it becomes a support crisis.
Frequently Asked Questions
What is the HubSpot Legacy CRM Card Migration Tool?
It's a developer-facing API update that lets app developers replace Legacy CRM Cards with React-powered App Cards using the migrate views endpoint. The swap happens asynchronously across all connected customer portals without requiring any manual action from those customers. It was released April 24, 2026.
When do Legacy CRM Cards go away in HubSpot?
HubSpot is sunsetting Legacy CRM Cards on October 31, 2026. After that date, any unmigrated Legacy CRM Card could disappear from customer CRM record views or stop functioning entirely. App developers need to complete their migration to App Cards before this deadline.
Do I need to do anything as a HubSpot portal admin?
Not technically, but you should act on the vendor side. Audit every third-party app installed in your portal that displays cards on CRM records. Contact each vendor and ask whether they've migrated to App Cards. If they haven't, push them for a timeline before October 31, 2026.
What's the difference between a Legacy CRM Card and an App Card?
Legacy CRM Cards were the original way apps embedded content into HubSpot record views. App Cards are built with React on HubSpot's UI Extensions framework, offering dynamic content, richer interactivity, and far more flexible layouts. App Cards are HubSpot's only supported path forward after October 31, 2026.
What does the migrate views API endpoint actually do?
When an app developer calls the migrate views API endpoint, HubSpot asynchronously updates all connected customer portals. It hides the Legacy CRM Card and replaces it with the new App Card inside each customer's CRM record views. Customers see the change on their next page load, with no action required from them.
Who is eligible to use the Legacy CRM Card Migration Tool?
Only app developers with existing Legacy CRM Cards whose apps have already been moved to HubSpot's Projects framework. Business owners and portal admins can't access this tool directly. The first step is running hs app migrate in the HubSpot CLI to get onto the Projects framework before calling the migration endpoint.
