●Change8

Migrating to Apollo Client @apollo/client@4.2.0-alpha.2

Version @apollo/client@4.2.0-alpha.2 introduces 2 breaking changes. This guide details how to update your code.

Released: 4/21/2026

2
Breaking Changes
2
Migration Steps
7
Affected Symbols

⚠️ Check Your Code

If you use any of these symbols, you need to read this guide:

useSuspenseQueryApolloClientApolloClient.DeclareDefaultOptionsApolloClient.DeclareDefaultOptions.WatchQueryApolloClient.DeclareDefaultOptions.QueryApolloClient.DeclareDefaultOptions.MutateApolloClient.TypeOverrides

Breaking Changes

●Issue #1

Using `defaultOptions` in the `ApolloClient` constructor without globally declaring the types for those options in `ApolloClient.DeclareDefaultOptions` will now result in a TypeScript error, whereas it was previously valid.

●Issue #2

When using 'modern' signatures (activated by declaring a non-optional property in `DeclareDefaultOptions` or setting `signatureStyle: "modern"`), manually specifying TypeScript generics (e.g., `useSuspenseQuery<MyData>(...)`) will produce a TypeScript error.

Migration Steps

  1. 1
    If you use `defaultOptions` in your `ApolloClient` constructor, you must now declare the types for those options globally in `apollo.d.ts` using `ApolloClient.DeclareDefaultOptions` to avoid TypeScript errors.
  2. 2
    If you rely on manually specified TypeScript generics for hooks/methods and wish to keep using 'classic' signatures, ensure you do not declare any non-optional properties in `DeclareDefaultOptions` or explicitly set `TypeOverrides { signatureStyle: "classic" }` in `apollo.d.ts`.

Release Summary

Apollo Client 4.2 introduces 'classic' and 'modern' signature styles, enhancing type safety by synchronizing hook/method return types with declared default options. This requires explicit type declaration for used default options to maintain type accuracy.

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