diff --git a/go.mod b/go.mod
index 6fd47f5..2077211 100644
--- a/go.mod
+++ b/go.mod
@@ -1,11 +1,10 @@
 module software.sslmate.com/src/certspotter
 
-go 1.19
+go 1.21
 
 require (
-	golang.org/x/exp v0.0.0-20230213192124-5e25df0256eb
-	golang.org/x/net v0.7.0
-	golang.org/x/sync v0.1.0
+	golang.org/x/net v0.14.0
+	golang.org/x/sync v0.3.0
 )
 
-require golang.org/x/text v0.7.0 // indirect
+require golang.org/x/text v0.12.0 // indirect
diff --git a/go.sum b/go.sum
index 019e5f7..c07f032 100644
--- a/go.sum
+++ b/go.sum
@@ -1,14 +1,6 @@
-golang.org/x/exp v0.0.0-20230203172020-98cc5a0785f9 h1:frX3nT9RkKybPnjyI+yvZh6ZucTZatCCEm9D47sZ2zo=
-golang.org/x/exp v0.0.0-20230203172020-98cc5a0785f9/go.mod h1:CxIveKay+FTh1D0yPZemJVgC/95VzuuOLq5Qi4xnoYc=
-golang.org/x/exp v0.0.0-20230213192124-5e25df0256eb h1:PaBZQdo+iSDyHT053FjUCgZQ/9uqVwPOcl7KSWhKn6w=
-golang.org/x/exp v0.0.0-20230213192124-5e25df0256eb/go.mod h1:CxIveKay+FTh1D0yPZemJVgC/95VzuuOLq5Qi4xnoYc=
-golang.org/x/net v0.5.0 h1:GyT4nK/YDHSqa1c4753ouYCDajOYKTja9Xb/OHtgvSw=
-golang.org/x/net v0.5.0/go.mod h1:DivGGAXEgPSlEBzxGzZI+ZLohi+xUj054jfeKui00ws=
-golang.org/x/net v0.7.0 h1:rJrUqqhjsgNp7KqAIc25s9pZnjU7TUcSY7HcVZjdn1g=
-golang.org/x/net v0.7.0/go.mod h1:2Tu9+aMcznHK/AK1HMvgo6xiTLG5rD5rZLDS+rp2Bjs=
-golang.org/x/sync v0.1.0 h1:wsuoTGHzEhffawBOhz5CYhcrV4IdKZbEyZjBMuTp12o=
-golang.org/x/sync v0.1.0/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
-golang.org/x/text v0.6.0 h1:3XmdazWV+ubf7QgHSTWeykHOci5oeekaGJBLkrkaw4k=
-golang.org/x/text v0.6.0/go.mod h1:mrYo+phRRbMaCq/xk9113O4dZlRixOauAjOtrjsXDZ8=
-golang.org/x/text v0.7.0 h1:4BRB4x83lYWy72KwLD/qYDuTu7q9PjSagHvijDw7cLo=
-golang.org/x/text v0.7.0/go.mod h1:mrYo+phRRbMaCq/xk9113O4dZlRixOauAjOtrjsXDZ8=
+golang.org/x/net v0.14.0 h1:BONx9s002vGdD9umnlX1Po8vOZmrgH34qlHcD1MfK14=
+golang.org/x/net v0.14.0/go.mod h1:PpSgVXXLK0OxS0F31C1/tv6XNguvCrnXIDrFMspZIUI=
+golang.org/x/sync v0.3.0 h1:ftCYgMx6zT/asHUrPw8BLLscYtGznsLAnjq5RH9P66E=
+golang.org/x/sync v0.3.0/go.mod h1:FU7BRWz2tNW+3quACPkgCx/L+uEAv1htQ0V83Z9Rj+Y=
+golang.org/x/text v0.12.0 h1:k+n5B8goJNdU7hSvEtMUz3d1Q6D/XW4COJSJR6fN0mc=
+golang.org/x/text v0.12.0/go.mod h1:TvPlkZtksWOMsz7fbANvkp4WM8x/WCo/om8BMLbz+aE=
diff --git a/merkletree/collapsed_tree.go b/merkletree/collapsed_tree.go
index a42b9e1..f3dcd25 100644
--- a/merkletree/collapsed_tree.go
+++ b/merkletree/collapsed_tree.go
@@ -13,7 +13,7 @@ import (
 	"encoding/json"
 	"fmt"
 	"math/bits"
-	"golang.org/x/exp/slices"
+	"slices"
 )
 
 type CollapsedTree struct {
diff --git a/monitor/sthdir.go b/monitor/sthdir.go
index a499647..b485e3c 100644
--- a/monitor/sthdir.go
+++ b/monitor/sthdir.go
@@ -10,13 +10,14 @@
 package monitor
 
 import (
+	"cmp"
 	"crypto/sha256"
 	"encoding/base64"
 	"encoding/binary"
 	"encoding/json"
 	"errors"
 	"fmt"
-	"golang.org/x/exp/slices"
+	"slices"
 	"io/fs"
 	"os"
 	"path/filepath"
@@ -44,7 +45,7 @@ func loadSTHsFromDir(dirPath string) ([]*ct.SignedTreeHead, error) {
 		}
 		sths = append(sths, sth)
 	}
-	slices.SortFunc(sths, func(a, b *ct.SignedTreeHead) bool { return a.TreeSize < b.TreeSize })
+	slices.SortFunc(sths, func(a, b *ct.SignedTreeHead) int { return cmp.Compare(a.TreeSize, b.TreeSize) })
 	return sths, nil
 }