diff --git a/go.mod b/go.mod
index d2b8c40..626d0c5 100644
--- a/go.mod
+++ b/go.mod
@@ -3,10 +3,10 @@ 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 v0.7.0
+	golang.org/x/sync v0.8.0
 )
 
-require github.com/creachadair/mds v0.15.5
+require github.com/creachadair/mds v0.16.0
 
 go 1.21
 
diff --git a/go.sum b/go.sum
index 30381d3..bc5ddcd 100644
--- a/go.sum
+++ b/go.sum
@@ -1,8 +1,8 @@
-github.com/creachadair/mds v0.15.5 h1:dhCbq/OzF4LiVkmmfy6Wm47w60CBF9iLU1J26ruCaE4=
-github.com/creachadair/mds v0.15.5/go.mod h1:4vrFYUzTXMJpMBU+OA292I6IUxKWCCfZkgXg+/kBZMo=
+github.com/creachadair/mds v0.16.0 h1:v6DlvKXClowXFg4hkjLCR1FEFiREMf0qgX+Lm5GsEKk=
+github.com/creachadair/mds v0.16.0/go.mod h1:4vrFYUzTXMJpMBU+OA292I6IUxKWCCfZkgXg+/kBZMo=
 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 v0.7.0 h1:YsImfSBoP9QPYL0xyKJPq0gcaJdG3rInoqxTWbfQu9M=
-golang.org/x/sync v0.7.0/go.mod h1:Czt+wKu1gCyEFDUtn0jG5QVvpJ6rzVqr5aXyt9drQfk=
+golang.org/x/sync v0.8.0 h1:3NFvSEYkUoMifnESzZl15y791HH1qU2xm6eCJU5ZPXQ=
+golang.org/x/sync v0.8.0/go.mod h1:Czt+wKu1gCyEFDUtn0jG5QVvpJ6rzVqr5aXyt9drQfk=
diff --git a/tools/go.mod b/tools/go.mod
index d3b0299..987c2d7 100644
--- a/tools/go.mod
+++ b/tools/go.mod
@@ -10,7 +10,7 @@ require (
 )
 
 require (
-	github.com/creachadair/mds v0.15.5 // indirect
-	golang.org/x/sync v0.7.0 // indirect
-	nhooyr.io/websocket v1.8.11 // indirect
+	github.com/creachadair/mds v0.16.0 // indirect
+	golang.org/x/sync v0.8.0 // indirect
+	nhooyr.io/websocket v1.8.17 // indirect
 )
diff --git a/tools/go.sum b/tools/go.sum
index 892530e..2a3a5b3 100644
--- a/tools/go.sum
+++ b/tools/go.sum
@@ -1,14 +1,14 @@
 github.com/creachadair/jrpc2 v1.2.0 h1:SXr0OgnwM0X18P+HccJP0uT3KGSDk/BCSRlJBvE2bMY=
 github.com/creachadair/jrpc2 v1.2.0/go.mod h1:66uKSdr6tR5ZeNvkIjDSbbVUtOv0UhjS/vcd8ECP7Iw=
-github.com/creachadair/mds v0.15.5 h1:dhCbq/OzF4LiVkmmfy6Wm47w60CBF9iLU1J26ruCaE4=
-github.com/creachadair/mds v0.15.5/go.mod h1:4vrFYUzTXMJpMBU+OA292I6IUxKWCCfZkgXg+/kBZMo=
+github.com/creachadair/mds v0.16.0 h1:v6DlvKXClowXFg4hkjLCR1FEFiREMf0qgX+Lm5GsEKk=
+github.com/creachadair/mds v0.16.0/go.mod h1:4vrFYUzTXMJpMBU+OA292I6IUxKWCCfZkgXg+/kBZMo=
 github.com/creachadair/wschannel v0.0.0-20240419143920-8a0c643c57cc h1:qum791hcmLtoBv26ID7y/Z8ZhooVHgsRwE+GQhfo5Ks=
 github.com/creachadair/wschannel v0.0.0-20240419143920-8a0c643c57cc/go.mod h1:4v2wftOqKNLbhuuZocaXeLehdf9rmvNJtUkenv0AYZw=
 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 v0.7.0 h1:YsImfSBoP9QPYL0xyKJPq0gcaJdG3rInoqxTWbfQu9M=
-golang.org/x/sync v0.7.0/go.mod h1:Czt+wKu1gCyEFDUtn0jG5QVvpJ6rzVqr5aXyt9drQfk=
-nhooyr.io/websocket v1.8.11 h1:f/qXNc2/3DpoSZkHt1DQu6rj4zGC8JmkkLkWss0MgN0=
-nhooyr.io/websocket v1.8.11/go.mod h1:rN9OFWIUwuxg4fR5tELlYC04bXYowCP9GX47ivo2l+c=
+golang.org/x/sync v0.8.0 h1:3NFvSEYkUoMifnESzZl15y791HH1qU2xm6eCJU5ZPXQ=
+golang.org/x/sync v0.8.0/go.mod h1:Czt+wKu1gCyEFDUtn0jG5QVvpJ6rzVqr5aXyt9drQfk=
+nhooyr.io/websocket v1.8.17 h1:KEVeLJkUywCKVsnLIDlD/5gtayKp8VoCkksHCGGfT9Y=
+nhooyr.io/websocket v1.8.17/go.mod h1:rN9OFWIUwuxg4fR5tELlYC04bXYowCP9GX47ivo2l+c=