diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
index 5250cf3..9ed6526 100644
--- a/.github/workflows/ci.yaml
+++ b/.github/workflows/ci.yaml
@@ -15,8 +15,10 @@ jobs:
           - ubuntu-latest
           - macos-latest
         go:
+          - '1.21'
           - '1.22'
           - '1.23'
+          - '1.24'
 
     runs-on: ${{ matrix.os }}
 
@@ -30,8 +32,19 @@ jobs:
 
     - run: go test -v -tags swiss_invariants
 
+  linux-noswissmap:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+
+      - name: Set up Go
+        uses: actions/setup-go@v4
+        with:
+          go-version: "1.24"
+
+      - run: GOEXPERIMENT=noswissmap go test -v
+
   linux-race:
-    name: go-linux-race
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v2
@@ -39,12 +52,12 @@ jobs:
       - name: Set up Go
         uses: actions/setup-go@v4
         with:
-          go-version: "1.23"
+          go-version: "1.24"
 
       - run: go test -v -race
 
+
   linux-32bit:
-    name: go-linux-32bit
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v2
@@ -52,7 +65,7 @@ jobs:
       - name: Set up Go
         uses: actions/setup-go@v4
         with:
-          go-version: "1.23"
+          go-version: "1.24"
 
       - run: GOARCH=386 go test -v -tags swiss_invariants
 
@@ -75,8 +88,8 @@ jobs:
                 lscpu | grep Endian &&
                 apt-get update &&
                 apt-get install -y wget &&
-                wget -q https://go.dev/dl/go1.23.6.linux-s390x.tar.gz &&
-                tar xzf go1.23.6.linux-s390x.tar.gz -C /usr/local &&
+                wget -q https://go.dev/dl/go1.24.0.linux-s390x.tar.gz &&
+                tar xzf go1.24.0.linux-s390x.tar.gz -C /usr/local &&
                 export PATH="$PATH:/usr/local/go/bin" &&
                 cd /swiss &&
                 go version &&
diff --git a/runtime_go1.20.go b/runtime_go1.20.go
index 069f685..31e38ba 100644
--- a/runtime_go1.20.go
+++ b/runtime_go1.20.go
@@ -17,12 +17,12 @@
 // bumping of the go versions supported by adjusting the build tags below. The
 // way go version tags work the tag for goX.Y will be declared for every
 // subsequent release. So go1.20 will be defined for go1.21, go1.22, etc. The
-// build tag "go1.20 && !go1.24" defines the range [go1.20, go1.24) (inclusive
-// on go1.20, exclusive on go1.24).
+// build tag "go1.20 && !go1.25" defines the range [go1.20, go1.25) (inclusive
+// on go1.20, exclusive on go1.25).
 
 // The untested_go_version flag enables building on any go version, intended
 // to ease testing against Go at tip.
-//go:build (go1.20 && !go1.24) || untested_go_version
+//go:build (go1.20 && !go1.25) || untested_go_version
 
 package swiss
 
@@ -59,17 +59,16 @@ type rtEface struct {
 }
 
 // From internal/abi/type.go:MapType
+// In go 1.24, this is a prefix of both abi.SwissMapType and abi.OldMapType.
 type rtMapType struct {
 	rtType
 	Key    *rtType
 	Elem   *rtType
 	Bucket *rtType // internal type representing a hash bucket
 	// function for hashing keys (ptr to key, seed) -> hash
-	Hasher     func(unsafe.Pointer, uintptr) uintptr
-	KeySize    uint8  // size of key slot
-	ValueSize  uint8  // size of elem slot
-	BucketSize uint16 // size of bucket
-	Flags      uint32
+	Hasher func(unsafe.Pointer, uintptr) uintptr
+
+	// Other fields are not relevant.
 }
 
 type rtTFlag uint8