chore: Update quic-go to v0.41.0, bump Go minimum to 1.21 (#6043)

Co-authored-by: Francis Lavoie <[email protected]>
Co-authored-by: Matt Holt <[email protected]>

11 files changed, 56 insertions, 85 deletions

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 0bca6b4d9..f0fb2520b 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -23,18 +23,18 @@ jobs:
           - macos-latest
           - windows-latest
         go: 
-          - '1.20'
           - '1.21'
+          - '1.22'
 
         include:
         # Set the minimum Go patch version for the given Go minor
         # Usable via ${{ matrix.GO_SEMVER }}
-        - go: '1.20'
-          GO_SEMVER: '~1.20.6'
-
         - go: '1.21'
           GO_SEMVER: '~1.21.0'
 
+        - go: '1.22'
+          GO_SEMVER: '~1.22.0-rc.2'
+
         # Set some variables per OS, usable via ${{ matrix.VAR }}
         # CADDY_BIN_PATH: the path to the compiled Caddy binary, for artifact publishing
         # SUCCESS: the typical value for $? per OS (Windows/pwsh returns 'True')
diff --git a/.github/workflows/cross-build.yml b/.github/workflows/cross-build.yml
index 4abfccbc7..e35045395 100644
--- a/.github/workflows/cross-build.yml
+++ b/.github/workflows/cross-build.yml
@@ -29,13 +29,13 @@ jobs:
           - 'darwin'
           - 'netbsd'
         go: 
-          - '1.21'
+          - '1.22'
 
         include:
         # Set the minimum Go patch version for the given Go minor
         # Usable via ${{ matrix.GO_SEMVER }}
-        - go: '1.21'
-          GO_SEMVER: '~1.21.0'
+        - go: '1.22'
+          GO_SEMVER: '~1.22.0-rc.2'
 
     runs-on: ubuntu-latest
     continue-on-error: true
diff --git a/.github/workflows/lint.yml b/.github/workflows/lint.yml
index b1fda44c4..d2762a621 100644
--- a/.github/workflows/lint.yml
+++ b/.github/workflows/lint.yml
@@ -31,12 +31,9 @@ jobs:
       - uses: actions/checkout@v4
       - uses: actions/setup-go@v5
         with:
-          go-version: '~1.21.0'
+          go-version: '~1.22.0-rc.2'
           check-latest: true
 
-          # Workaround for https://github.com/golangci/golangci-lint-action/issues/135
-          skip-pkg-cache: true
-
       - name: golangci-lint
         uses: golangci/golangci-lint-action@v3
         with:
@@ -57,5 +54,5 @@ jobs:
       - name: govulncheck
         uses: golang/govulncheck-action@v1
         with:
-          go-version-input: '~1.21.0'
+          go-version-input: '~1.22.0-rc.2'
           check-latest: true
diff --git a/README.md b/README.md
index 6dd046887..e5f99efdf 100644
--- a/README.md
+++ b/README.md
@@ -87,7 +87,7 @@ See [our online documentation](https://caddyserver.com/docs/install) for other i
 
 Requirements:
 
-- [Go 1.20 or newer](https://golang.org/dl/)
+- [Go 1.21 or newer](https://golang.org/dl/)
 
 ### For development
 
diff --git a/go.mod b/go.mod
index 17948a875..2f116af31 100644
--- a/go.mod
+++ b/go.mod
@@ -1,6 +1,8 @@
 module github.com/caddyserver/caddy/v2
 
-go 1.20
+go 1.21
+
+toolchain go1.21.4
 
 require (
 	github.com/BurntSushi/toml v1.3.2
@@ -16,7 +18,7 @@ require (
 	github.com/klauspost/cpuid/v2 v2.2.5
 	github.com/mholt/acmez v1.2.0
 	github.com/prometheus/client_golang v1.18.0
-	github.com/quic-go/quic-go v0.40.1
+	github.com/quic-go/quic-go v0.41.0
 	github.com/smallstep/certificates v0.25.0
 	github.com/smallstep/nosql v0.6.0
 	github.com/smallstep/truststore v0.12.1
@@ -59,7 +61,6 @@ require (
 	github.com/onsi/ginkgo/v2 v2.13.2 // indirect
 	github.com/pmezard/go-difflib v1.0.0 // indirect
 	github.com/quic-go/qpack v0.4.0 // indirect
-	github.com/quic-go/qtls-go1-20 v0.4.1 // indirect
 	github.com/smallstep/go-attestation v0.4.4-0.20230627102604-cf579e53cbd2 // indirect
 	github.com/x448/float16 v0.8.4 // indirect
 	github.com/zeebo/blake3 v0.2.3 // indirect
diff --git a/go.sum b/go.sum
index 5910c3228..9276581a4 100644
--- a/go.sum
+++ b/go.sum
@@ -2,10 +2,13 @@ cloud.google.com/go v0.26.0/go.mod h1:aQUYkXzVsufM+DwF1aE+0xfcU+56JwCaLick0ClmMT
 cloud.google.com/go v0.34.0/go.mod h1:aQUYkXzVsufM+DwF1aE+0xfcU+56JwCaLick0ClmMTw=
 cloud.google.com/go v0.110.7 h1:rJyC7nWRg2jWGZ4wSJ5nY65GTdYJkg0cd/uXb+ACI6o=
 cloud.google.com/go/compute v1.23.3 h1:6sVlXXBmbd7jNX0Ipq0trII3e4n1/MsADLK6a+aiVlk=
+cloud.google.com/go/compute v1.23.3/go.mod h1:VCgBUoMnIVIR0CscqQiPJLAG25E3ZRZMzcFZeQ+h8CI=
 cloud.google.com/go/compute/metadata v0.2.3 h1:mg4jlk7mCAj6xXp9UJ4fjI9VUI5rubuGBW5aJ7UnBMY=
+cloud.google.com/go/compute/metadata v0.2.3/go.mod h1:VAV5nSsACxMJvgaAuX6Pk2AawlZn8kiOGuCv6gTkwuA=
 cloud.google.com/go/iam v1.1.2 h1:gacbrBdWcoVmGLozRuStX45YKvJtzIjJdAolzUs1sm4=
 cloud.google.com/go/iam v1.1.2/go.mod h1:A5avdyVL2tCppe4unb0951eI9jreack+RJ0/d+KUZOU=
 cloud.google.com/go/kms v1.15.2 h1:lh6qra6oC4AyWe5fUUUBe/S27k12OHAleOOOw6KakdE=
+cloud.google.com/go/kms v1.15.2/go.mod h1:3hopT4+7ooWRCjc2DxgnpESFxhIraaI2IpAVUEhbT/w=
 filippo.io/edwards25519 v1.0.0 h1:0wAIcmJUqRdI8IJ/3eGi5/HwXZWPujYXXlkrQogz0Ek=
 filippo.io/edwards25519 v1.0.0/go.mod h1:N1IkdkCkiLB6tki+MYJoSx2JTY9NUlxZE7eHn5EwJns=
 github.com/AndreasBriese/bbloom v0.0.0-20190825152654-46b345b51c96 h1:cTp8I5+VIoKjsnZuH8vjyaysT/ses3EvZeaV/1UkF2M=
@@ -30,11 +33,13 @@ github.com/Shopify/toxiproxy v2.1.4+incompatible/go.mod h1:OXgGpZ6Cli1/URJOF1DMx
 github.com/VividCortex/gohistogram v1.0.0/go.mod h1:Pf5mBqqDxYaXu3hDrrU+w6nw50o/4+TcAqDqk/vUH7g=
 github.com/afex/hystrix-go v0.0.0-20180502004556-fa1af6a1f4f5/go.mod h1:SkGFH1ia65gfNATL8TAiHDNxPzPdmEL5uirI2Uyuz6c=
 github.com/alecthomas/assert/v2 v2.2.1 h1:XivOgYcduV98QCahG8T5XTezV5bylXe+lBxLG2K2ink=
+github.com/alecthomas/assert/v2 v2.2.1/go.mod h1:pXcQ2Asjp247dahGEmsZ6ru0UVwnkhktn7S0bBDLxvQ=
 github.com/alecthomas/chroma/v2 v2.2.0/go.mod h1:vf4zrexSH54oEjJ7EdB65tGNHmH3pGZmVkgTP5RHvAs=
 github.com/alecthomas/chroma/v2 v2.9.1 h1:0O3lTQh9FxazJ4BYE/MOi/vDGuHn7B+6Bu902N2UZvU=
 github.com/alecthomas/chroma/v2 v2.9.1/go.mod h1:4TQu7gdfuPjSh76j78ietmqh9LiurGF0EpseFXdKMBw=
 github.com/alecthomas/repr v0.0.0-20220113201626-b1b626ac65ae/go.mod h1:2kn6fqh/zIyPLmm3ugklbEi5hg5wS435eygvNfaDQL8=
 github.com/alecthomas/repr v0.2.0 h1:HAzS41CIzNW5syS8Mf9UwXhNH1J9aix/BvDRf1Ml2Yk=
+github.com/alecthomas/repr v0.2.0/go.mod h1:Fr0507jx4eOXV7AlPV6AVZLYrLIuIeSOWtW57eE/O/4=
 github.com/alecthomas/template v0.0.0-20160405071501-a0175ee3bccc/go.mod h1:LOuyumcjzFXgccqObfd/Ljyb9UuFJ6TxHnclSeseNhc=
 github.com/alecthomas/template v0.0.0-20190718012654-fb15b899a751/go.mod h1:LOuyumcjzFXgccqObfd/Ljyb9UuFJ6TxHnclSeseNhc=
 github.com/alecthomas/units v0.0.0-20151022065526-2efee857e7cf/go.mod h1:ybxpYRFXyAe+OPACYpWeL0wqObRcbAqCMya13uyzqw0=
@@ -53,6 +58,7 @@ github.com/aryann/difflib v0.0.0-20210328193216-ff5ff6dc229b/go.mod h1:DAHtR1m6l
 github.com/aws/aws-lambda-go v1.13.3/go.mod h1:4UKl9IzQMoD+QF79YdCuzCwp8VbmG4VAQwij/eHl5CU=
 github.com/aws/aws-sdk-go v1.27.0/go.mod h1:KmX6BPdI08NWTb3/sm4ZGu5ShLoqVDhKgpiN924inxo=
 github.com/aws/aws-sdk-go v1.46.4 h1:48tKgtm9VMPkb6y7HuYlsfhQmoIRAsTEXTsWLVlty4M=
+github.com/aws/aws-sdk-go v1.46.4/go.mod h1:aVsgQcEevwlmQ7qHE9I3h+dtQgpqhFB+i8Phjh7fkwI=
 github.com/aws/aws-sdk-go-v2 v0.18.0/go.mod h1:JWVYvqSMppoMJC0x5wdwiImzgXTI9FuZwxzkQq9wy+g=
 github.com/beorn7/perks v0.0.0-20180321164747-3a771d992973/go.mod h1:Dwedo/Wpr24TaqPxmxbtue+5NUziq4I4S80YR8gNf3Q=
 github.com/beorn7/perks v1.0.0/go.mod h1:KWe93zE9D1o94FZ5RNwFwVgaQK1VOXiVxmqh+CedLV8=
@@ -177,6 +183,7 @@ github.com/golang/glog v1.1.2/go.mod h1:zR+okUeTbrL6EL3xHUDxZuEtGv04p5shwip1+mL/
 github.com/golang/groupcache v0.0.0-20160516000752-02826c3e7903/go.mod h1:cIg4eruTrX1D+g88fzRXU5OdNfaM+9IcxsU14FzY7Hc=
 github.com/golang/groupcache v0.0.0-20190702054246-869f871628b6/go.mod h1:cIg4eruTrX1D+g88fzRXU5OdNfaM+9IcxsU14FzY7Hc=
 github.com/golang/groupcache v0.0.0-20210331224755-41bb18bfe9da h1:oI5xCqsCo564l8iNU+DwB5epxmsaqB+rhGL0m5jtYqE=
+github.com/golang/groupcache v0.0.0-20210331224755-41bb18bfe9da/go.mod h1:cIg4eruTrX1D+g88fzRXU5OdNfaM+9IcxsU14FzY7Hc=
 github.com/golang/mock v1.1.1/go.mod h1:oTYuIxOrZwtPieC+H1uAHpcLFnEyAGVDL/k47Jfbm0A=
 github.com/golang/protobuf v1.2.0/go.mod h1:6lQm79b+lXiMfvg/cZm0SGofjICqVBUtrP5yJMmIC1U=
 github.com/golang/protobuf v1.3.1/go.mod h1:6lQm79b+lXiMfvg/cZm0SGofjICqVBUtrP5yJMmIC1U=
@@ -191,6 +198,7 @@ github.com/golang/snappy v0.0.4/go.mod h1:/XxbfmMg8lxefKM7IXC3fBNl/7bRcc72aCRzEW
 github.com/google/btree v0.0.0-20180813153112-4030bb1f1f0c/go.mod h1:lNA+9X1NB3Zf8V7Ke586lFgjr2dZNuvo3lPJSGZ5JPQ=
 github.com/google/btree v1.0.0/go.mod h1:lNA+9X1NB3Zf8V7Ke586lFgjr2dZNuvo3lPJSGZ5JPQ=
 github.com/google/btree v1.1.2 h1:xf4v41cLI2Z6FxbKm+8Bu+m8ifhj15JuZ9sa0jZCMUU=
+github.com/google/btree v1.1.2/go.mod h1:qOPhT0dTNdNzV6Z/lhRX0YXUafgPLFUh+gZMl761Gm4=
 github.com/google/cel-go v0.15.1 h1:iTgVZor2x9okXtmTrqO8cg4uvqIeaBcWhXtruaWFMYQ=
 github.com/google/cel-go v0.15.1/go.mod h1:YzWEoI07MC/a/wj9in8GeVatqfypkldgBlwXh9bCwqY=
 github.com/google/certificate-transparency-go v1.0.21/go.mod h1:QeJfpSbVSfYc7RgB3gJFj9cbuQMMchQxrWXz8Ruopmg=
@@ -201,9 +209,11 @@ github.com/google/go-cmp v0.3.0/go.mod h1:8QqcDgzrUqlUb/G2PQTWiueGozuR1884gddMyw
 github.com/google/go-cmp v0.3.1/go.mod h1:8QqcDgzrUqlUb/G2PQTWiueGozuR1884gddMywk6iLU=
 github.com/google/go-cmp v0.5.5/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
 github.com/google/go-cmp v0.6.0 h1:ofyhxvXcZhMsU5ulbFiLKl/XBFqE1GSq7atu8tAmTRI=
+github.com/google/go-cmp v0.6.0/go.mod h1:17dUlkBOakJ0+DkrSSNjCkIjxS6bF9zb3elmeNGIjoY=
 github.com/google/go-tpm v0.9.0 h1:sQF6YqWMi+SCXpsmS3fd21oPy/vSddwZry4JnmltHVk=
 github.com/google/go-tpm v0.9.0/go.mod h1:FkNVkc6C+IsvDI9Jw1OveJmxGZUUaKxtrpOS47QWKfU=
 github.com/google/go-tpm-tools v0.4.1 h1:gYU6iwRo0tY3V6NDnS6m+XYog+b3g6YFhHQl3sYaUL4=
+github.com/google/go-tpm-tools v0.4.1/go.mod h1:w03m0jynhTo7puXTYoyfpNOMqyQ9SB7sixnKWsS/1L0=
 github.com/google/go-tspi v0.3.0 h1:ADtq8RKfP+jrTyIWIZDIYcKOMecRqNJFOew2IT0Inus=
 github.com/google/go-tspi v0.3.0/go.mod h1:xfMGI3G0PhxCdNVcYr1C4C+EizojDg/TXuX5by8CiHI=
 github.com/google/gofuzz v1.0.0/go.mod h1:dBl0BpW6vV/+mYPU4Po3pmUjxk6FQPldtuIdl/M65Eg=
@@ -211,12 +221,15 @@ github.com/google/pprof v0.0.0-20231212022811-ec68065c825e h1:bwOy7hAFd0C91URzMI
 github.com/google/pprof v0.0.0-20231212022811-ec68065c825e/go.mod h1:czg5+yv1E0ZGTi6S6vVK1mke0fV+FaUhNGcd6VRS9Ik=
 github.com/google/renameio v0.1.0/go.mod h1:KWCgfxg9yswjAJkECMjeO8J8rahYeXnNhOm40UhjYkI=
 github.com/google/s2a-go v0.1.7 h1:60BLSyTrOV4/haCDW4zb1guZItoSq8foHCXrAnjBo/o=
+github.com/google/s2a-go v0.1.7/go.mod h1:50CgR4k1jNlWBu4UfS4AcfhVe1r6pdZPygJ3R8F0Qdw=
 github.com/google/uuid v1.0.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
 github.com/google/uuid v1.1.1/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
 github.com/google/uuid v1.3.1 h1:KjJaJ9iWZ3jOFZIf1Lqf4laDRCasjl0BCmnEGxkdLb4=
 github.com/google/uuid v1.3.1/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
 github.com/googleapis/enterprise-certificate-proxy v0.3.2 h1:Vie5ybvEvT75RniqhfFxPRy3Bf7vr3h0cechB90XaQs=
+github.com/googleapis/enterprise-certificate-proxy v0.3.2/go.mod h1:VLSiSSBs/ksPL8kq3OBOQ6WRI2QnaFynd1DCjZ62+V0=
 github.com/googleapis/gax-go/v2 v2.12.0 h1:A+gCJKdRfqXkr+BIRGtZLibNXf0m1f9E4HG56etFpas=
+github.com/googleapis/gax-go/v2 v2.12.0/go.mod h1:y+aIqrI5eb1YGMVJfuV3185Ts/D7qKpsEkdD5+I6QGU=
 github.com/gopherjs/gopherjs v0.0.0-20181017120253-0766667cb4d1/go.mod h1:wJfORRmW1u3UXTncJ5qlYoELFm8eSnnEO6hX4iZ3EWY=
 github.com/gorilla/context v0.0.0-20160226214623-1ea25387ff6f/go.mod h1:kBGZzfjB9CEq2AlWe17Uuf7NDRt0dE0s8S51q0aT7Yg=
 github.com/gorilla/context v1.1.1/go.mod h1:kBGZzfjB9CEq2AlWe17Uuf7NDRt0dE0s8S51q0aT7Yg=
@@ -252,6 +265,7 @@ github.com/hashicorp/mdns v1.0.0/go.mod h1:tL+uN++7HEJ6SQLQ2/p+z2pH24WQKWjBPkE0m
 github.com/hashicorp/memberlist v0.1.3/go.mod h1:ajVTdAv/9Im8oMAAj5G31PhhMCZJV2pPBoIllUwCN7I=
 github.com/hashicorp/serf v0.8.2/go.mod h1:6hOLApaqBFA1NXqRQAsxw9QxuDEvNxSQRwA/JwenrHc=
 github.com/hexops/gotextdiff v1.0.3 h1:gitA9+qJrrTCsiCl7+kh75nPqQt1cx4ZkudSTLoUqJM=
+github.com/hexops/gotextdiff v1.0.3/go.mod h1:pSWU5MAI3yDq+fZBTazCSJysOMbxWL1BSow5/V2vxeg=
 github.com/hpcloud/tail v1.0.0/go.mod h1:ab1qPbhIpdTxEkNHXyeSf5vhxWSCs/tWer42PpOxQnU=
 github.com/huandu/xstrings v1.3.3 h1:/Gcsuc1x8JVbJ9/rlye4xZnVAbEkGauT8lbebqcQws4=
 github.com/huandu/xstrings v1.3.3/go.mod h1:y5/lhBue+AyNmUVz9RLU9xbLR0o4KIIExikq4ovT0aE=
@@ -314,6 +328,7 @@ github.com/jackc/puddle v1.3.0/go.mod h1:m4B5Dj62Y0fbyuIc15OsIqK0+JU8nkqQjsgx7dv
 github.com/jessevdk/go-flags v1.4.0/go.mod h1:4FA24M0QyGHXBuZZK/XkWh8h0e1EYbRYJSGM75WSRxI=
 github.com/jmespath/go-jmespath v0.0.0-20180206201540-c2b33e8439af/go.mod h1:Nht3zPeWKUH0NzdCt2Blrr5ys8VGpn0CEB0cQHVjt7k=
 github.com/jmespath/go-jmespath v0.4.0 h1:BEgLn5cpjn8UN1mAw4NjwDrS35OdebyEtFe+9YPoQUg=
+github.com/jmespath/go-jmespath v0.4.0/go.mod h1:T8mJZnbsbmF+m6zOOFylbeCJqk5+pHWvzYPziyZiYoo=
 github.com/jonboulle/clockwork v0.1.0/go.mod h1:Ii8DK3G1RaLaWxj9trq07+26W01tbo22gdxWY5EU2bo=
 github.com/json-iterator/go v1.1.6/go.mod h1:+SdeFBvtyEkXs7REEP0seUULqWtbJapLOCVDaaPEHmU=
 github.com/json-iterator/go v1.1.7/go.mod h1:KdQUCv79m/52Kvf8AW2vK1V8akMuk1QjK/uOdHXbAo4=
@@ -334,15 +349,18 @@ github.com/kr/logfmt v0.0.0-20140226030751-b84e30acd515/go.mod h1:+0opPa2QZZtGFB
 github.com/kr/pretty v0.1.0/go.mod h1:dAy3ld7l9f0ibDNOQOHHMYYIIbhfbHSm3C4ZsoJORNo=
 github.com/kr/pretty v0.2.0/go.mod h1:ipq/a2n7PKx3OHsz4KJII5eveXtPO4qwEXGdVfWzfnI=
 github.com/kr/pretty v0.3.1 h1:flRD4NNwYAUpkphVc1HcthR4KEIFJ65n8Mw5qdRn3LE=
+github.com/kr/pretty v0.3.1/go.mod h1:hoEshYVHaxMs3cyo3Yncou5ZscifuDolrwPKZanG3xk=
 github.com/kr/pty v1.1.1/go.mod h1:pFQYn66WHrOpPYNljwOMqo10TkYh1fy3cYio2l3bCsQ=
 github.com/kr/pty v1.1.8/go.mod h1:O1sed60cT9XZ5uDucP5qwvh+TE3NnUj51EiZO/lmSfw=
 github.com/kr/text v0.1.0/go.mod h1:4Jbv+DJW3UT/LiOwJeYQe1efqtUx/iVham/4vfdArNI=
 github.com/kr/text v0.2.0 h1:5Nx0Ya0ZqY2ygV366QzturHI13Jq95ApcVaJBhpS+AY=
+github.com/kr/text v0.2.0/go.mod h1:eLer722TekiGuMkidMxC/pM04lWEeraHUUmBw8l2grE=
 github.com/lib/pq v1.0.0/go.mod h1:5WUZQaWbwv1U+lTReE5YruASi9Al49XbQIvNi/34Woo=
 github.com/lib/pq v1.1.0/go.mod h1:5WUZQaWbwv1U+lTReE5YruASi9Al49XbQIvNi/34Woo=
 github.com/lib/pq v1.2.0/go.mod h1:5WUZQaWbwv1U+lTReE5YruASi9Al49XbQIvNi/34Woo=
 github.com/lib/pq v1.10.2/go.mod h1:AlVN5x4E4T544tWzH6hKfbfQvm3HdbOxrmggDNAPY9o=
 github.com/lib/pq v1.10.9 h1:YXG7RB+JIjhP29X+OtkiDnYaXQwpS4JEWq7dtCCRUEw=
+github.com/lib/pq v1.10.9/go.mod h1:AlVN5x4E4T544tWzH6hKfbfQvm3HdbOxrmggDNAPY9o=
 github.com/libdns/libdns v0.2.1 h1:Wu59T7wSHRgtA0cfxC+n1c/e+O3upJGWytknkmFEDis=
 github.com/libdns/libdns v0.2.1/go.mod h1:yQCXzk1lEZmmCPa857bnk4TsOiqYasqpyOEeSObbb40=
 github.com/lightstep/lightstep-tracer-common/golang/gogo v0.0.0-20190605223551-bc2310a04743/go.mod h1:qklhhLq1aX+mtWk9cPHPzaBjWImj5ULL6C7HFJtXQMM=
@@ -413,6 +431,7 @@ github.com/onsi/ginkgo/v2 v2.13.2 h1:Bi2gGVkfn6gQcjNjZJVO8Gf0FHzMPf2phUei9tejVMs
 github.com/onsi/ginkgo/v2 v2.13.2/go.mod h1:XStQ8QcGwLyF4HdfcZB8SFOS/MWCgDuXMSBe6zrvLgM=
 github.com/onsi/gomega v1.4.3/go.mod h1:ex+gbHU/CVuBBDIJjb2X0qEXbFg53c61hWP/1CpauHY=
 github.com/onsi/gomega v1.29.0 h1:KIA/t2t5UBzoirT4H9tsML45GEbo3ouUnBHsCfD2tVg=
+github.com/onsi/gomega v1.29.0/go.mod h1:9sxs+SwGrKI0+PWe4Fxa9tFQQBG5xSsSbMXOI8PPpoQ=
 github.com/op/go-logging v0.0.0-20160315200505-970db520ece7/go.mod h1:HzydrMdWErDVzsI23lYNej1Htcns9BCg93Dk0bBINWk=
 github.com/opentracing-contrib/go-observer v0.0.0-20170622124052-a52f23424492/go.mod h1:Ngi6UdF0k5OKD5t5wlmGhe/EDKPoUM3BXZSSfIuJbis=
 github.com/opentracing/basictracer-go v1.0.0/go.mod h1:QfBfYuafItcjQuMwinw9GhYKwFXS9KnPs5lxoYwgW74=
@@ -428,6 +447,7 @@ github.com/pborman/uuid v1.2.0/go.mod h1:X/NO0urCmaxf9VXbdlT7C2Yzkj2IKimNn4k+gtP
 github.com/pelletier/go-toml v1.2.0/go.mod h1:5z9KED0ma1S8pY6P1sdut58dfprrGBbd/94hg7ilaic=
 github.com/performancecopilot/speed v3.0.0+incompatible/go.mod h1:/CLtqpZ5gBg1M9iaPbIdPPGyKcA8hKdoy6hAWba7Yac=
 github.com/peterbourgon/diskv/v3 v3.0.1 h1:x06SQA46+PKIUftmEujdwSEpIx8kR+M9eLYsUxeYveU=
+github.com/peterbourgon/diskv/v3 v3.0.1/go.mod h1:kJ5Ny7vLdARGU3WUuy6uzO6T0nb/2gWcT1JiBvRmb5o=
 github.com/pierrec/lz4 v1.0.2-0.20190131084431-473cd7ce01a1/go.mod h1:3/3N9NVKO0jef7pBehbT1qWhCMrIgbYNnFAZCqQ5LRc=
 github.com/pierrec/lz4 v2.0.5+incompatible/go.mod h1:pdkljMzZIN41W+lC3N2tnIh5sFi+IEE17M5jbnwPHcY=
 github.com/pires/go-proxyproto v0.7.0 h1:IukmRewDQFWC7kfnb66CSomk2q/seBuilHBYFwyq0Hs=
@@ -441,6 +461,7 @@ github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZb
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/posener/complete v1.1.1/go.mod h1:em0nMJCgc9GFtwrmVmEMR/ZL6WyhyjMBndrE9hABlRI=
 github.com/prashantv/gostub v1.1.0 h1:BTyx3RfQjRHnUWaGF9oQos79AlQ5k8WNktv7VGvVH4g=
+github.com/prashantv/gostub v1.1.0/go.mod h1:A5zLQHz7ieHGG7is6LLXLz7I8+3LZzsrV0P1IAHhP5U=
 github.com/prometheus/client_golang v0.9.1/go.mod h1:7SWBe2y4D6OKWSNQJUaRYU/AaXPKyh/dDVn+NZz0KFw=
 github.com/prometheus/client_golang v0.9.3-0.20190127221311-3c4408c8b829/go.mod h1:p2iRAGwDERtqlqzRXnrOVns+ignqQo//hLXqYxZYVNs=
 github.com/prometheus/client_golang v1.0.0/go.mod h1:db9x61etRT2tGnBNRi70OPL5FsnadC4Ky3P0J6CfImo=
@@ -467,14 +488,13 @@ github.com/prometheus/procfs v0.12.0 h1:jluTpSng7V9hY0O2R9DzzJHYb2xULk9VTR1V1R/k
 github.com/prometheus/procfs v0.12.0/go.mod h1:pcuDEFsWDnvcgNzo4EEweacyhjeA9Zk3cnaOZAZEfOo=
 github.com/quic-go/qpack v0.4.0 h1:Cr9BXA1sQS2SmDUWjSofMPNKmvF6IiIfDRmgU0w1ZCo=
 github.com/quic-go/qpack v0.4.0/go.mod h1:UZVnYIfi5GRk+zI9UMaCPsmZ2xKJP7XBUvVyT1Knj9A=
-github.com/quic-go/qtls-go1-20 v0.4.1 h1:D33340mCNDAIKBqXuAvexTNMUByrYmFYVfKfDN5nfFs=
-github.com/quic-go/qtls-go1-20 v0.4.1/go.mod h1:X9Nh97ZL80Z+bX/gUXMbipO6OxdiDi58b/fMC9mAL+k=
-github.com/quic-go/quic-go v0.40.1 h1:X3AGzUNFs0jVuO3esAGnTfvdgvL4fq655WaOi1snv1Q=
-github.com/quic-go/quic-go v0.40.1/go.mod h1:PeN7kuVJ4xZbxSv/4OX6S1USOX8MJvydwpTx31vx60c=
+github.com/quic-go/quic-go v0.41.0 h1:aD8MmHfgqTURWNJy48IYFg2OnxwHT3JL7ahGs73lb4k=
+github.com/quic-go/quic-go v0.41.0/go.mod h1:qCkNjqczPEvgsOnxZ0eCD14lv+B2LHlFAB++CNOh9hA=
 github.com/rcrowley/go-metrics v0.0.0-20181016184325-3113b8401b8a/go.mod h1:bCqnVzQkZxMG4s8nGwiZ5l3QUCyqpo9Y+/ZMZ9VjZe4=
 github.com/rogpeppe/fastuuid v0.0.0-20150106093220-6724a57986af/go.mod h1:XWv6SoW27p1b0cqNHllgS5HIMJraePCO15w5zCzIWYg=
 github.com/rogpeppe/go-internal v1.3.0/go.mod h1:M8bDsm7K2OlrFYOpmOWEs/qY81heoFRclV5y23lUDJ4=
 github.com/rogpeppe/go-internal v1.10.0 h1:TMyTOH3F/DB16zRVcYyreMH6GnZZrwQVAoYjRBZyWFQ=
+github.com/rogpeppe/go-internal v1.10.0/go.mod h1:UQnix2H7Ngw/k4C5ijL5+65zddjncjaFoBhdsK/akog=
 github.com/rs/xid v1.2.1/go.mod h1:+uKXf+4Djp6Md1KODXJxgGQPKngRmWyn10oCKFzNHOQ=
 github.com/rs/xid v1.5.0 h1:mKX4bl4iPYJtEIxp6CYiUuLQ/8DYMoz0PUdtGgMFRVc=
 github.com/rs/xid v1.5.0/go.mod h1:trrq9SKmegXys3aeAKXMUTdJsYXVwGY3RLcfgqegfbg=
@@ -488,6 +508,7 @@ github.com/ryanuber/columnize v0.0.0-20160712163229-9b3edd62028f/go.mod h1:sm1tb
 github.com/samuel/go-zookeeper v0.0.0-20190923202752-2cc03de413da/go.mod h1:gi+0XIa01GRL2eRQVjQkKGqKF3SF9vZR/HnPullcV2E=
 github.com/satori/go.uuid v1.2.0/go.mod h1:dA0hQrYB0VpLJoorglMZABFdXlWrHn1NEOzdhQKdks0=
 github.com/schollz/jsonstore v1.1.0 h1:WZBDjgezFS34CHI+myb4s8GGpir3UMpy7vWoCeO0n6E=
+github.com/schollz/jsonstore v1.1.0/go.mod h1:15c6+9guw8vDRyozGjN3FoILt0wpruJk9Pi66vjaZfg=
 github.com/sean-/seed v0.0.0-20170313163322-e2103e2c3529/go.mod h1:DxrIzT+xaE7yg65j358z/aeFdxmN0P9QXhEzd20vsDc=
 github.com/shopspring/decimal v0.0.0-20180709203117-cd690d0c9e24/go.mod h1:M+9NzErvs504Cn4c5DxATwIqPbtswREoFCre64PpcG4=
 github.com/shopspring/decimal v1.2.0 h1:abSATXmQEYyShuxI4/vyW3tV1MrKAJzCZ/0zLUXYbsQ=
@@ -503,6 +524,7 @@ github.com/sirupsen/logrus v1.9.3/go.mod h1:naHLuLoDiP4jHNo9R0sCBMtWGeIprob74mVs
 github.com/slackhq/nebula v1.6.1 h1:/OCTR3abj0Sbf2nGoLUrdDXImrCv0ZVFpVPP5qa0DsM=
 github.com/slackhq/nebula v1.6.1/go.mod h1:UmkqnXe4O53QwToSl/gG7sM4BroQwAB7dd4hUaT6MlI=
 github.com/smallstep/assert v0.0.0-20200723003110-82e2b9b3b262 h1:unQFBIznI+VYD1/1fApl1A+9VcBk+9dcqGfnePY87LY=
+github.com/smallstep/assert v0.0.0-20200723003110-82e2b9b3b262/go.mod h1:MyOHs9Po2fbM1LHej6sBUT8ozbxmMOFG+E+rx/GSGuc=
 github.com/smallstep/certificates v0.25.0 h1:WWihtjQ7SprnRxDV44mBp8t5SMsNO5EWsQaEwy1rgFg=
 github.com/smallstep/certificates v0.25.0/go.mod h1:thJmekMKUplKYip+la99Lk4IwQej/oVH/zS9PVMagEE=
 github.com/smallstep/go-attestation v0.4.4-0.20230627102604-cf579e53cbd2 h1:UIAS8DTWkeclraEGH2aiJPyNPu16VbT41w4JoBlyFfU=
@@ -590,7 +612,9 @@ go.opencensus.io v0.20.1/go.mod h1:6WKK9ahsWS3RSO+PY9ZHZUfv2irvY6gN279GOPZjmmk=
 go.opencensus.io v0.20.2/go.mod h1:6WKK9ahsWS3RSO+PY9ZHZUfv2irvY6gN279GOPZjmmk=
 go.opencensus.io v0.22.2/go.mod h1:yxeiOL68Rb0Xd1ddK5vPZ/oVn4vY4Ynel7k9FzqtOIw=
 go.opencensus.io v0.24.0 h1:y73uSU6J157QMP2kn2r30vwW1A2W2WFwSCGnAVxeaD0=
+go.opencensus.io v0.24.0/go.mod h1:vNK8G9p7aAivkbmorf4v+7Hgx+Zs0yY+0fOtgBfjQKo=
 go.opentelemetry.io/contrib/instrumentation/google.golang.org/grpc/otelgrpc v0.46.1 h1:SpGay3w+nEwMpfVnbqOLH5gY52/foP8RE8UzTZ1pdSE=
+go.opentelemetry.io/contrib/instrumentation/google.golang.org/grpc/otelgrpc v0.46.1/go.mod h1:4UoMYEZOC0yN/sPGH76KPkkU7zgiEWYWL9vwmbnTJPE=
 go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp v0.46.1 h1:aFJWCqJMNjENlcleuuOkGAPH82y0yULBScfXcIEdS24=
 go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp v0.46.1/go.mod h1:sEGXWArGqc3tVa+ekntsN65DmVbVeW+7lTKTjZF3/Fo=
 go.opentelemetry.io/contrib/propagators/autoprop v0.42.0 h1:s2RzYOAqHVgG23q8fPWYChobUoZM6rJZ98EnylJr66w=
@@ -630,6 +654,7 @@ go.uber.org/atomic v1.6.0/go.mod h1:sABNBOSYdrvTF6hTgEIbc7YasKWGhgEQZyfxyTvoXHQ=
 go.uber.org/automaxprocs v1.5.3 h1:kWazyxZUrS3Gs4qUpbwo5kEIMGe/DAvi5Z4tl2NW4j8=
 go.uber.org/automaxprocs v1.5.3/go.mod h1:eRbA25aqJrxAbsLO0xy5jVwPt7FQnRgjW+efnwa1WM0=
 go.uber.org/goleak v1.3.0 h1:2K3zAYmnTNqV73imy9J1T3WC+gmCePx2hEGkimedGto=
+go.uber.org/goleak v1.3.0/go.mod h1:CoHD4mav9JJNrW/WLlf7HGZPjdw8EucARQHekz1X6bE=
 go.uber.org/mock v0.3.0 h1:3mUxI1No2/60yUYax92Pt8eNOEecx2D3lcXZh2NEZJo=
 go.uber.org/mock v0.3.0/go.mod h1:a6FSlNadKUHUa9IP5Vyt1zh4fC7uAwxMutEAscFbkZc=
 go.uber.org/multierr v1.1.0/go.mod h1:wR5kodmAFQ0UK8QlbwjlSNy0Z68gJhDJUG5sjR94q/0=
@@ -700,6 +725,7 @@ golang.org/x/net v0.19.0/go.mod h1:CfAk/cbD4CthTvqiEl8NpboMuiuOYsAr/7NOjZJtv1U=
 golang.org/x/oauth2 v0.0.0-20180821212333-d2e6202438be/go.mod h1:N/0e6XlmueqKjAGxoOufVs8QHGRruUQn6yWY3a++T0U=
 golang.org/x/oauth2 v0.0.0-20190226205417-e64efc72b421/go.mod h1:gOpvHmFTYa4IltrdGE7lF6nIHvwfUNPOp7c8zoXwtLw=
 golang.org/x/oauth2 v0.15.0 h1:s8pnnxNVzjWyrvYdFUQq5llS1PX2zhPXmccZv99h7uQ=
+golang.org/x/oauth2 v0.15.0/go.mod h1:q48ptWNTY5XWf+JNten23lcvHpLJ0ZSxF5ttTHKVCAM=
 golang.org/x/sync v0.0.0-20180314180146-1d60e4601c6f/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sync v0.0.0-20181108010431-42b317875d0f/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sync v0.0.0-20181221193216-37e7f081c4d4/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
@@ -765,6 +791,7 @@ golang.org/x/text v0.14.0/go.mod h1:18ZOQIKpY8NJVqYksKHtTdi31H5itFRjB5/qKTNYzSU=
 golang.org/x/time v0.0.0-20180412165947-fbb02b2291d2/go.mod h1:tRJNPiyCQ0inRvYxbN9jk5I+vvW/OXSQhTDSoE431IQ=
 golang.org/x/time v0.0.0-20191024005414-555d28b269f0/go.mod h1:tRJNPiyCQ0inRvYxbN9jk5I+vvW/OXSQhTDSoE431IQ=
 golang.org/x/time v0.5.0 h1:o7cqy6amK/52YcAKIPlM3a+Fpj35zvRj2TP+e1xFSfk=
+golang.org/x/time v0.5.0/go.mod h1:3BpzKBy/shNhVucY/MWOyx10tF3SFh9QdLuxbVysPQM=
 golang.org/x/tools v0.0.0-20180221164845-07fd8470d635/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
 golang.org/x/tools v0.0.0-20180828015842-6cd1fcedba52/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
 golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
@@ -792,16 +819,19 @@ golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8T
 golang.org/x/xerrors v0.0.0-20200804184101-5ec99f83aff1/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 google.golang.org/api v0.3.1/go.mod h1:6wY9I6uQWHQ8EM57III9mq/AjF+i8G65rmVagqKMtkk=
 google.golang.org/api v0.154.0 h1:X7QkVKZBskztmpPKWQXgjJRPA2dJYrL6r+sYPRLj050=
+google.golang.org/api v0.154.0/go.mod h1:qhSMkM85hgqiokIYsrRyKxrjfBeIhgl4Z2JmeRkYylc=
 google.golang.org/appengine v1.1.0/go.mod h1:EbEs0AVv82hx2wNQdGPgUI5lhzA/G0D9YwlJXL52JkM=
 google.golang.org/appengine v1.2.0/go.mod h1:xpcJRLb0r/rnEns0DIKYYv+WjYCduHsrkT7/EB5XEv4=
 google.golang.org/appengine v1.4.0/go.mod h1:xpcJRLb0r/rnEns0DIKYYv+WjYCduHsrkT7/EB5XEv4=
 google.golang.org/appengine v1.6.8 h1:IhEN5q69dyKagZPYMSdIjS2HqprW324FRQZJcGqPAsM=
+google.golang.org/appengine v1.6.8/go.mod h1:1jJ3jBArFh5pcgW8gCtRJnepW8FzD1V44FJffLiz/Ds=
 google.golang.org/genproto v0.0.0-20180817151627-c66870c02cf8/go.mod h1:JiN7NxoALGmiZfu7CAH4rXhgtRTLTxftemlI0sWmxmc=
 google.golang.org/genproto v0.0.0-20190307195333-5fe7a883aa19/go.mod h1:VzzqZJRnGkLBvHegQrXjBqPurQTc5/KpmUdxsrq26oE=
 google.golang.org/genproto v0.0.0-20190425155659-357c62f0e4bb/go.mod h1:VzzqZJRnGkLBvHegQrXjBqPurQTc5/KpmUdxsrq26oE=
 google.golang.org/genproto v0.0.0-20190530194941-fb225487d101/go.mod h1:z3L6/3dTEVtUr6QSP8miRzeRqwQOioJ9I66odjN4I7s=
 google.golang.org/genproto v0.0.0-20190819201941-24fa4b261c55/go.mod h1:DMBHOl98Agz4BDEuKkezgsaosCRResVns1a3J2ZsMNc=
 google.golang.org/genproto v0.0.0-20231120223509-83a465c0220f h1:Vn+VyHU5guc9KjB5KrjI2q0wCOWEOIh0OEsleqakHJg=
+google.golang.org/genproto v0.0.0-20231120223509-83a465c0220f/go.mod h1:nWSwAFPb+qfNJXsoeO3Io7zf4tMSfN8EA8RlDA04GhY=
 google.golang.org/genproto/googleapis/api v0.0.0-20231120223509-83a465c0220f h1:2yNACc1O40tTnrsbk9Cv6oxiW8pxI/pXj0wRtdlYmgY=
 google.golang.org/genproto/googleapis/api v0.0.0-20231120223509-83a465c0220f/go.mod h1:Uy9bTZJqmfrw2rIBxgGLnamc78euZULUBrLZ9XTITKI=
 google.golang.org/genproto/googleapis/rpc v0.0.0-20231127180814-3a041ad873d4 h1:DC7wcm+i+P1rN3Ff07vL+OndGg5OhNddHyTA+ocPqYE=
@@ -826,6 +856,7 @@ gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8
 gopkg.in/check.v1 v1.0.0-20180628173108-788fd7840127/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/check.v1 v1.0.0-20190902080502-41f04d3bba15/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c h1:Hei/4ADfdWqJk1ZMxUNpqntNwaWcugrBjAiHlqqRiVk=
+gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c/go.mod h1:JHkPIbrfpd72SG/EVd6muEfDQjcINNoR0C8j2r3qZ4Q=
 gopkg.in/cheggaaa/pb.v1 v1.0.25/go.mod h1:V/YB90LKu/1FcN3WVnfiiE5oMCibMjukxqG/qStrOgw=
 gopkg.in/errgo.v2 v2.1.0/go.mod h1:hNsd1EY+bozCKY1Ytp96fpM3vjJbqLJn88ws8XvfDNI=
 gopkg.in/fsnotify.v1 v1.4.7/go.mod h1:Tz8NjZHkW78fSQdbUxIjBTcgA1z1m8ZHf0WmKUhAMys=
diff --git a/modules/caddyhttp/app.go b/modules/caddyhttp/app.go
index 46846d4f8..0ae0af39e 100644
--- a/modules/caddyhttp/app.go
+++ b/modules/caddyhttp/app.go
@@ -20,9 +20,7 @@ import (
 	"fmt"
 	"net"
 	"net/http"
-	"runtime"
 	"strconv"
-	"strings"
 	"sync"
 	"time"
 
@@ -328,15 +326,9 @@ func (app *App) Provision(ctx caddy.Context) error {
 
 // Validate ensures the app's configuration is valid.
 func (app *App) Validate() error {
-	isGo120 := strings.Contains(runtime.Version(), "go1.20")
-
 	// each server must use distinct listener addresses
 	lnAddrs := make(map[string]string)
 	for srvName, srv := range app.Servers {
-		if isGo120 && srv.EnableFullDuplex {
-			app.logger.Warn("enable_full_duplex is not supported in Go 1.20, use a build made with Go 1.21 or later", zap.String("server", srvName))
-		}
-
 		for _, addr := range srv.Listen {
 			listenAddr, err := caddy.ParseNetworkAddress(addr)
 			if err != nil {
diff --git a/modules/caddyhttp/duplex_go120.go b/modules/caddyhttp/duplex_go120.go
deleted file mode 100644
index 065ccf282..000000000
--- a/modules/caddyhttp/duplex_go120.go
+++ /dev/null
@@ -1,26 +0,0 @@
-// Copyright 2015 Matthew Holt and The Caddy Authors
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-//go:build !go1.21
-
-package caddyhttp
-
-import (
-	"net/http"
-)
-
-func enableFullDuplex(w http.ResponseWriter) error {
-	// Do nothing, Go 1.20 and earlier do not support full duplex
-	return nil
-}
diff --git a/modules/caddyhttp/duplex_go121.go b/modules/caddyhttp/duplex_go121.go
deleted file mode 100644
index a17d3afe7..000000000
--- a/modules/caddyhttp/duplex_go121.go
+++ /dev/null
@@ -1,26 +0,0 @@
-// Copyright 2015 Matthew Holt and The Caddy Authors
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-//go:build go1.21
-
-package caddyhttp
-
-import (
-	"net/http"
-)
-
-func enableFullDuplex(w http.ResponseWriter) error {
-	//nolint:bodyclose
-	return http.NewResponseController(w).EnableFullDuplex()
-}
diff --git a/modules/caddyhttp/replacer.go b/modules/caddyhttp/replacer.go
index ef5084e3a..10258da01 100644
--- a/modules/caddyhttp/replacer.go
+++ b/modules/caddyhttp/replacer.go
@@ -19,7 +19,6 @@ import (
 	"context"
 	"crypto/ecdsa"
 	"crypto/ed25519"
-	"crypto/elliptic"
 	"crypto/rsa"
 	"crypto/sha256"
 	"crypto/tls"
@@ -470,7 +469,11 @@ func marshalPublicKey(pubKey any) ([]byte, error) {
 	case *rsa.PublicKey:
 		return asn1.Marshal(key)
 	case *ecdsa.PublicKey:
-		return elliptic.Marshal(key.Curve, key.X, key.Y), nil
+		e, err := key.ECDH()
+		if err != nil {
+			return nil, err
+		}
+		return e.Bytes(), nil
 	case ed25519.PublicKey:
 		return key, nil
 	}
diff --git a/modules/caddyhttp/server.go b/modules/caddyhttp/server.go
index bece87470..1dec60795 100644
--- a/modules/caddyhttp/server.go
+++ b/modules/caddyhttp/server.go
@@ -302,9 +302,8 @@ func (s *Server) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 	// enable full-duplex for HTTP/1, ensuring the entire
 	// request body gets consumed before writing the response
 	if s.EnableFullDuplex {
-		// TODO: Remove duplex_go12*.go abstraction once our
-		// minimum Go version is 1.21 or later
-		err := enableFullDuplex(w)
+		//nolint:bodyclose
+		err := http.NewResponseController(w).EnableFullDuplex()
 		if err != nil {
 			s.accessLogger.Warn("failed to enable full duplex", zap.Error(err))
 		}