diff --git a/go.mod b/go.mod
index 02587e5..610e42b 100644
--- a/go.mod
+++ b/go.mod
@@ -3,7 +3,7 @@ module github.com/creachadair/jrpc2
 require (
 	github.com/fortytw2/leaktest v1.3.0
 	github.com/google/go-cmp v0.6.0
-	golang.org/x/sync v0.8.0
+	golang.org/x/sync v0.9.0
 )
 
 require (
diff --git a/go.sum b/go.sum
index d41de70..afbe7be 100644
--- a/go.sum
+++ b/go.sum
@@ -10,8 +10,8 @@ golang.org/x/exp/typeparams v0.0.0-20231108232855-2478ac86f678 h1:1P7xPZEwZMoBoz
 golang.org/x/exp/typeparams v0.0.0-20231108232855-2478ac86f678/go.mod h1:AbB0pIl9nAr9wVwH+Z2ZpaocVmF5I4GyWCDIsVjR0bk=
 golang.org/x/mod v0.17.0 h1:zY54UmvipHiNd+pm+m0x9KhZ9hl1/7QNMyxXbc6ICqA=
 golang.org/x/mod v0.17.0/go.mod h1:hTbmBsO62+eylJbnUtE2MGJUyE7QWk4xUqPFrRgJ+7c=
-golang.org/x/sync v0.8.0 h1:3NFvSEYkUoMifnESzZl15y791HH1qU2xm6eCJU5ZPXQ=
-golang.org/x/sync v0.8.0/go.mod h1:Czt+wKu1gCyEFDUtn0jG5QVvpJ6rzVqr5aXyt9drQfk=
+golang.org/x/sync v0.9.0 h1:fEo0HyrW1GIgZdpbhCRO0PkJajUS5H9IFUztCgEo2jQ=
+golang.org/x/sync v0.9.0/go.mod h1:Czt+wKu1gCyEFDUtn0jG5QVvpJ6rzVqr5aXyt9drQfk=
 golang.org/x/tools v0.21.1-0.20240531212143-b6235391adb3 h1:SHq4Rl+B7WvyM4XODon1LXtP7gcG49+7Jubt1gWWswY=
 golang.org/x/tools v0.21.1-0.20240531212143-b6235391adb3/go.mod h1:bqv7PJ/TtlrzgJKhOAGdDUkUltQapRik/UEHubLVBWo=
 honnef.co/go/tools v0.5.1 h1:4bH5o3b5ZULQ4UrBmP+63W9r7qIkqJClEA9ko5YKx+I=
diff --git a/tools/go.mod b/tools/go.mod
index 9cc1cff..626fb9b 100644
--- a/tools/go.mod
+++ b/tools/go.mod
@@ -6,11 +6,11 @@ toolchain go1.23.1
 
 require (
 	github.com/creachadair/jrpc2 v1.3.0
-	github.com/creachadair/wschannel v0.0.0-20240812143019-767d903641b9
+	github.com/creachadair/wschannel v0.0.0-20241109184048-225ae55119e4
 )
 
 require (
 	github.com/coder/websocket v1.8.12 // indirect
 	github.com/creachadair/mds v0.21.4 // indirect
-	golang.org/x/sync v0.8.0 // indirect
+	golang.org/x/sync v0.9.0 // indirect
 )
diff --git a/tools/go.sum b/tools/go.sum
index 92147d4..0a6563c 100644
--- a/tools/go.sum
+++ b/tools/go.sum
@@ -4,11 +4,11 @@ github.com/creachadair/jrpc2 v1.3.0 h1:CALlqNxD3u16U+gzNGoSQMYAr9uLCxjrB3D6Yu9+e
 github.com/creachadair/jrpc2 v1.3.0/go.mod h1:rOu1u3LG86IEhMlG/N6FaHuP/leA5PjyuTQvDjE/G9k=
 github.com/creachadair/mds v0.21.4 h1:osKuLbjkV7YswBnhuTJh1lCDkqZMQnNfFVn0j8wLpz8=
 github.com/creachadair/mds v0.21.4/go.mod h1:1ltMWZd9yXhaHEoZwBialMaviWVUpRPvMwVP7saFAzM=
-github.com/creachadair/wschannel v0.0.0-20240812143019-767d903641b9 h1:RmzgVZNFyAkv9ogYygr4+8a7ohY2AFIIr5mcxJITh3I=
-github.com/creachadair/wschannel v0.0.0-20240812143019-767d903641b9/go.mod h1:y1EUhJKHdMHM+/6l+5hz/wh9IDT/5L8U3TAQS1IWwcE=
+github.com/creachadair/wschannel v0.0.0-20241109184048-225ae55119e4 h1:1IFc+mRoTEaZkBgXPnZRLJIP/LY9Nmjh4DMaaKPx3OQ=
+github.com/creachadair/wschannel v0.0.0-20241109184048-225ae55119e4/go.mod h1:O6n2aiFhUF5mRG7byZE70aQyVQgfbG0/oI1s8WxWpLI=
 github.com/fortytw2/leaktest v1.3.0 h1:u8491cBMTQ8ft8aeV+adlcytMZylmA5nnwwkRZjI8vw=
 github.com/fortytw2/leaktest v1.3.0/go.mod h1:jDsjWgpAGjm2CA7WthBh/CdZYEPF31XHquHwclZch5g=
 github.com/google/go-cmp v0.6.0 h1:ofyhxvXcZhMsU5ulbFiLKl/XBFqE1GSq7atu8tAmTRI=
 github.com/google/go-cmp v0.6.0/go.mod h1:17dUlkBOakJ0+DkrSSNjCkIjxS6bF9zb3elmeNGIjoY=
-golang.org/x/sync v0.8.0 h1:3NFvSEYkUoMifnESzZl15y791HH1qU2xm6eCJU5ZPXQ=
-golang.org/x/sync v0.8.0/go.mod h1:Czt+wKu1gCyEFDUtn0jG5QVvpJ6rzVqr5aXyt9drQfk=
+golang.org/x/sync v0.9.0 h1:fEo0HyrW1GIgZdpbhCRO0PkJajUS5H9IFUztCgEo2jQ=
+golang.org/x/sync v0.9.0/go.mod h1:Czt+wKu1gCyEFDUtn0jG5QVvpJ6rzVqr5aXyt9drQfk=