diff --git a/.github/actions/package/Dockerfile b/.github/actions/package/Dockerfile
index 44b679218e..d3d8d28f78 100644
--- a/.github/actions/package/Dockerfile
+++ b/.github/actions/package/Dockerfile
@@ -1,4 +1,4 @@
-ARG BASE_IMAGE=rust:1.55.0-buster
+ARG BASE_IMAGE=rust:1.56.0-buster
 FROM $BASE_IMAGE
 WORKDIR /linkerd
 RUN apt-get update && \
diff --git a/.github/workflows/advisory.yml b/.github/workflows/advisory.yml
index fd1589cfe4..425900ffc0 100644
--- a/.github/workflows/advisory.yml
+++ b/.github/workflows/advisory.yml
@@ -24,7 +24,7 @@ jobs:
     timeout-minutes: 40
     runs-on: ubuntu-latest
     container:
-      image: docker://rust:1.55.0-buster
+      image: docker://rust:1.56.0-buster
     permissions:
       contents: read
     strategy:
diff --git a/.github/workflows/coverage.yml b/.github/workflows/coverage.yml
index 49e4c9932e..7983d1266a 100644
--- a/.github/workflows/coverage.yml
+++ b/.github/workflows/coverage.yml
@@ -11,7 +11,7 @@ jobs:
     runs-on: ubuntu-latest
     timeout-minutes: 30
     container:
-      image: docker://rust:1.55.0-buster
+      image: docker://rust:1.56.0-buster
       options: --security-opt seccomp=unconfined
     steps:
       - uses: actions/checkout@1e204e9a9253d643386038d443f96446fa156a97
diff --git a/.github/workflows/rust.yml b/.github/workflows/rust.yml
index dac2ffef2a..39f1aa9eed 100644
--- a/.github/workflows/rust.yml
+++ b/.github/workflows/rust.yml
@@ -24,7 +24,7 @@ jobs:
     timeout-minutes: 5
     runs-on: ubuntu-latest
     container:
-      image: docker://rust:1.55.0-buster
+      image: docker://rust:1.56.0-buster
     permissions:
       contents: read
     steps:
@@ -37,7 +37,7 @@ jobs:
     timeout-minutes: 20
     runs-on: ubuntu-latest
     container:
-      image: docker://rust:1.55.0-buster
+      image: docker://rust:1.56.0-buster
     permissions:
       contents: read
     steps:
@@ -49,7 +49,7 @@ jobs:
     timeout-minutes: 5
     runs-on: ubuntu-latest
     container:
-      image: docker://rust:1.55.0-buster
+      image: docker://rust:1.56.0-buster
     permissions:
       contents: read
     steps:
diff --git a/Dockerfile b/Dockerfile
index eec73b4bc4..898c7f395f 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -17,7 +17,7 @@
 #     :; docker buildx build . --load
 
 # Please make changes via update-rust-version.sh
-ARG RUST_IMAGE=rust:1.55.0-buster
+ARG RUST_IMAGE=rust:1.56.0-buster
 
 # Use an arbitrary ~recent edge release image to get the proxy
 # identity-initializing and linkerd-await wrappers.
@@ -41,7 +41,7 @@ RUN --mount=type=cache,target=/var/lib/apt/lists \
 WORKDIR /usr/src/linkerd2-proxy
 COPY . .
 RUN --mount=type=cache,target=target \
-  --mount=type=cache,from=rust:1.55.0-buster,source=/usr/local/cargo,target=/usr/local/cargo \
+  --mount=type=cache,from=rust:1.56.0-buster,source=/usr/local/cargo,target=/usr/local/cargo \
   mkdir -p /out && \
   if [ -n "$PROXY_UNOPTIMIZED" ]; then \
   (cd linkerd2-proxy && /usr/bin/time -v cargo build --locked --features="$PROXY_FEATURES") && \
diff --git a/hyper-balance/Cargo.toml b/hyper-balance/Cargo.toml
index 66c6fa0141..bafa6161a5 100644
--- a/hyper-balance/Cargo.toml
+++ b/hyper-balance/Cargo.toml
@@ -3,7 +3,7 @@ name = "hyper-balance"
 version = "0.1.0"
 authors = ["Linkerd Developers <cncf-linkerd-dev@lists.cncf.io>"]
 license = "Apache-2.0"
-edition = "2018"
+edition = "2021"
 publish = false
 
 [dependencies]
diff --git a/linkerd/addr/Cargo.toml b/linkerd/addr/Cargo.toml
index f7be77dfce..55a52b5e1d 100644
--- a/linkerd/addr/Cargo.toml
+++ b/linkerd/addr/Cargo.toml
@@ -3,7 +3,7 @@ name = "linkerd-addr"
 version = "0.1.0"
 authors = ["Linkerd Developers <cncf-linkerd-dev@lists.cncf.io>"]
 license = "Apache-2.0"
-edition = "2018"
+edition = "2021"
 publish = false
 
 [dependencies]
diff --git a/linkerd/addr/fuzz/Cargo.toml b/linkerd/addr/fuzz/Cargo.toml
index 837355486e..264d75bfa4 100644
--- a/linkerd/addr/fuzz/Cargo.toml
+++ b/linkerd/addr/fuzz/Cargo.toml
@@ -3,7 +3,7 @@ name = "linkerd-addr-fuzz"
 version = "0.0.0"
 authors = ["Linkerd Developers <cncf-linkerd-dev@lists.cncf.io>"]
 publish = false
-edition = "2018"
+edition = "2021"
 
 [package.metadata]
 cargo-fuzz = true
diff --git a/linkerd/app/Cargo.toml b/linkerd/app/Cargo.toml
index 8200c12f9f..28e49b4f7a 100644
--- a/linkerd/app/Cargo.toml
+++ b/linkerd/app/Cargo.toml
@@ -3,7 +3,7 @@ name = "linkerd-app"
 version = "0.1.0"
 authors = ["Linkerd Developers <cncf-linkerd-dev@lists.cncf.io>"]
 license = "Apache-2.0"
-edition = "2018"
+edition = "2021"
 publish = false
 description = """
 Configures and executes the proxy
diff --git a/linkerd/app/admin/Cargo.toml b/linkerd/app/admin/Cargo.toml
index 9fbe87c8a3..cc82039a45 100644
--- a/linkerd/app/admin/Cargo.toml
+++ b/linkerd/app/admin/Cargo.toml
@@ -3,7 +3,7 @@ name = "linkerd-app-admin"
 version = "0.1.0"
 authors = ["Linkerd Developers <cncf-linkerd-dev@lists.cncf.io>"]
 license = "Apache-2.0"
-edition = "2018"
+edition = "2021"
 publish = false
 description = """
 The linkerd proxy's admin server.
diff --git a/linkerd/app/admin/src/server/mod.rs b/linkerd/app/admin/src/server.rs
similarity index 99%
rename from linkerd/app/admin/src/server/mod.rs
rename to linkerd/app/admin/src/server.rs
index 9faf54c717..eb26442fb3 100644
--- a/linkerd/app/admin/src/server/mod.rs
+++ b/linkerd/app/admin/src/server.rs
@@ -224,7 +224,7 @@ mod tests {
                     .unwrap();
                 let f = admin.clone().oneshot(r);
                 timeout(TIMEOUT, f).await.expect("timeout").expect("call")
-            };};
+            }};
         }
 
         assert_eq!(call!().status(), StatusCode::SERVICE_UNAVAILABLE);
diff --git a/linkerd/app/core/Cargo.toml b/linkerd/app/core/Cargo.toml
index 18db691afb..c06036be4b 100644
--- a/linkerd/app/core/Cargo.toml
+++ b/linkerd/app/core/Cargo.toml
@@ -3,7 +3,7 @@ name = "linkerd-app-core"
 version = "0.1.0"
 authors = ["Linkerd Developers <cncf-linkerd-dev@lists.cncf.io>"]
 license = "Apache-2.0"
-edition = "2018"
+edition = "2021"
 publish = false
 description = """
 Core infrastructure for the proxy application
diff --git a/linkerd/app/core/src/errors/mod.rs b/linkerd/app/core/src/errors.rs
similarity index 100%
rename from linkerd/app/core/src/errors/mod.rs
rename to linkerd/app/core/src/errors.rs
diff --git a/linkerd/app/core/src/metrics/mod.rs b/linkerd/app/core/src/metrics.rs
similarity index 100%
rename from linkerd/app/core/src/metrics/mod.rs
rename to linkerd/app/core/src/metrics.rs
diff --git a/linkerd/app/core/src/proxy/mod.rs b/linkerd/app/core/src/proxy.rs
similarity index 100%
rename from linkerd/app/core/src/proxy/mod.rs
rename to linkerd/app/core/src/proxy.rs
diff --git a/linkerd/app/core/src/telemetry/mod.rs b/linkerd/app/core/src/telemetry.rs
similarity index 100%
rename from linkerd/app/core/src/telemetry/mod.rs
rename to linkerd/app/core/src/telemetry.rs
diff --git a/linkerd/app/core/src/transport/mod.rs b/linkerd/app/core/src/transport.rs
similarity index 100%
rename from linkerd/app/core/src/transport/mod.rs
rename to linkerd/app/core/src/transport.rs
diff --git a/linkerd/app/gateway/Cargo.toml b/linkerd/app/gateway/Cargo.toml
index de01dd2e6a..9ccd962f0c 100644
--- a/linkerd/app/gateway/Cargo.toml
+++ b/linkerd/app/gateway/Cargo.toml
@@ -3,7 +3,7 @@ name = "linkerd-app-gateway"
 version = "0.1.0"
 authors = ["Linkerd Developers <cncf-linkerd-dev@lists.cncf.io>"]
 license = "Apache-2.0"
-edition = "2018"
+edition = "2021"
 publish = false
 
 [dependencies]
diff --git a/linkerd/app/gateway/src/lib.rs b/linkerd/app/gateway/src/lib.rs
index 6c45d56f56..7089c73548 100644
--- a/linkerd/app/gateway/src/lib.rs
+++ b/linkerd/app/gateway/src/lib.rs
@@ -26,7 +26,7 @@ use linkerd_app_inbound::{
     policy, Inbound,
 };
 use linkerd_app_outbound::{self as outbound, Outbound};
-use std::{convert::TryInto, fmt};
+use std::fmt;
 use thiserror::Error;
 use tracing::debug_span;
 
diff --git a/linkerd/app/inbound/Cargo.toml b/linkerd/app/inbound/Cargo.toml
index 14b7bda181..b5fce49035 100644
--- a/linkerd/app/inbound/Cargo.toml
+++ b/linkerd/app/inbound/Cargo.toml
@@ -3,7 +3,7 @@ name = "linkerd-app-inbound"
 version = "0.1.0"
 authors = ["Linkerd Developers <cncf-linkerd-dev@lists.cncf.io>"]
 license = "Apache-2.0"
-edition = "2018"
+edition = "2021"
 publish = false
 description = """
 Configures and runs the inbound proxy
diff --git a/linkerd/app/inbound/fuzz/Cargo.toml b/linkerd/app/inbound/fuzz/Cargo.toml
index 170afb67f0..4da445a925 100644
--- a/linkerd/app/inbound/fuzz/Cargo.toml
+++ b/linkerd/app/inbound/fuzz/Cargo.toml
@@ -4,7 +4,7 @@ name = "linkerd-app-inbound-fuzz"
 version = "0.0.0"
 authors = ["Automatically generated"]
 publish = false
-edition = "2018"
+edition = "2021"
 
 [package.metadata]
 cargo-fuzz = true
diff --git a/linkerd/app/inbound/src/http/mod.rs b/linkerd/app/inbound/src/http.rs
similarity index 100%
rename from linkerd/app/inbound/src/http/mod.rs
rename to linkerd/app/inbound/src/http.rs
diff --git a/linkerd/app/inbound/src/http/router.rs b/linkerd/app/inbound/src/http/router.rs
index 961fcbd771..89a08c3108 100644
--- a/linkerd/app/inbound/src/http/router.rs
+++ b/linkerd/app/inbound/src/http/router.rs
@@ -278,7 +278,7 @@ impl<A> svc::stack::RecognizeRoute<http::Request<A>> for LogicalPerRequest {
         use linkerd_app_core::{
             http_request_authority_addr, http_request_host_addr, CANONICAL_DST_HEADER,
         };
-        use std::{convert::TryInto, str::FromStr};
+        use std::str::FromStr;
 
         // Try to read a logical named address from the request. First check the canonical-dst
         // header as set by the client proxy; otherwise fallback to the request's `:authority` or
diff --git a/linkerd/app/inbound/src/metrics/mod.rs b/linkerd/app/inbound/src/metrics.rs
similarity index 100%
rename from linkerd/app/inbound/src/metrics/mod.rs
rename to linkerd/app/inbound/src/metrics.rs
diff --git a/linkerd/app/inbound/src/metrics/error/mod.rs b/linkerd/app/inbound/src/metrics/error.rs
similarity index 100%
rename from linkerd/app/inbound/src/metrics/error/mod.rs
rename to linkerd/app/inbound/src/metrics/error.rs
diff --git a/linkerd/app/inbound/src/policy/mod.rs b/linkerd/app/inbound/src/policy.rs
similarity index 100%
rename from linkerd/app/inbound/src/policy/mod.rs
rename to linkerd/app/inbound/src/policy.rs
diff --git a/linkerd/app/inbound/src/policy/authorize/mod.rs b/linkerd/app/inbound/src/policy/authorize.rs
similarity index 100%
rename from linkerd/app/inbound/src/policy/authorize/mod.rs
rename to linkerd/app/inbound/src/policy/authorize.rs
diff --git a/linkerd/app/inbound/src/policy/discover.rs b/linkerd/app/inbound/src/policy/discover.rs
index 4bd242eeba..c8f5f1b5de 100644
--- a/linkerd/app/inbound/src/policy/discover.rs
+++ b/linkerd/app/inbound/src/policy/discover.rs
@@ -12,7 +12,7 @@ use linkerd_server_policy::{
     Authentication, Authorization, Network, Protocol, ServerPolicy, Suffix,
 };
 use linkerd_tonic_watch::StreamWatch;
-use std::{convert::TryInto, net::IpAddr};
+use std::net::IpAddr;
 
 #[derive(Clone, Debug)]
 pub(super) struct Discover<S> {
diff --git a/linkerd/app/integration/Cargo.toml b/linkerd/app/integration/Cargo.toml
index 9dec0674f1..a0e5772153 100644
--- a/linkerd/app/integration/Cargo.toml
+++ b/linkerd/app/integration/Cargo.toml
@@ -3,7 +3,7 @@ name = "linkerd-app-integration"
 version = "0.1.0"
 authors = ["Linkerd Developers <cncf-linkerd-dev@lists.cncf.io>"]
 license = "Apache-2.0"
-edition = "2018"
+edition = "2021"
 publish = false
 description = """
 Proxy integration tests
diff --git a/linkerd/app/integration/src/tests/mod.rs b/linkerd/app/integration/src/tests.rs
similarity index 100%
rename from linkerd/app/integration/src/tests/mod.rs
rename to linkerd/app/integration/src/tests.rs
diff --git a/linkerd/app/integration/src/tests/telemetry/mod.rs b/linkerd/app/integration/src/tests/telemetry.rs
similarity index 100%
rename from linkerd/app/integration/src/tests/telemetry/mod.rs
rename to linkerd/app/integration/src/tests/telemetry.rs
diff --git a/linkerd/app/outbound/Cargo.toml b/linkerd/app/outbound/Cargo.toml
index 36c38c37f7..6f481cee90 100644
--- a/linkerd/app/outbound/Cargo.toml
+++ b/linkerd/app/outbound/Cargo.toml
@@ -3,7 +3,7 @@ name = "linkerd-app-outbound"
 version = "0.1.0"
 authors = ["Linkerd Developers <cncf-linkerd-dev@lists.cncf.io>"]
 license = "Apache-2.0"
-edition = "2018"
+edition = "2021"
 publish = false
 description = """
 Configures and runs the outbound proxy
diff --git a/linkerd/app/outbound/src/http/mod.rs b/linkerd/app/outbound/src/http.rs
similarity index 100%
rename from linkerd/app/outbound/src/http/mod.rs
rename to linkerd/app/outbound/src/http.rs
diff --git a/linkerd/app/outbound/src/metrics/mod.rs b/linkerd/app/outbound/src/metrics.rs
similarity index 100%
rename from linkerd/app/outbound/src/metrics/mod.rs
rename to linkerd/app/outbound/src/metrics.rs
diff --git a/linkerd/app/outbound/src/metrics/error/mod.rs b/linkerd/app/outbound/src/metrics/error.rs
similarity index 100%
rename from linkerd/app/outbound/src/metrics/error/mod.rs
rename to linkerd/app/outbound/src/metrics/error.rs
diff --git a/linkerd/app/outbound/src/tcp/mod.rs b/linkerd/app/outbound/src/tcp.rs
similarity index 100%
rename from linkerd/app/outbound/src/tcp/mod.rs
rename to linkerd/app/outbound/src/tcp.rs
diff --git a/linkerd/app/test/Cargo.toml b/linkerd/app/test/Cargo.toml
index 3138ff4725..e9b3b0e421 100644
--- a/linkerd/app/test/Cargo.toml
+++ b/linkerd/app/test/Cargo.toml
@@ -3,7 +3,7 @@ name = "linkerd-app-test"
 version = "0.1.0"
 authors = ["Linkerd Developers <cncf-linkerd-dev@lists.cncf.io>"]
 license = "Apache-2.0"
-edition = "2018"
+edition = "2021"
 publish = false
 description = """
 Proxy integration tests
diff --git a/linkerd/cache/Cargo.toml b/linkerd/cache/Cargo.toml
index 759fced3b0..4d06991430 100644
--- a/linkerd/cache/Cargo.toml
+++ b/linkerd/cache/Cargo.toml
@@ -3,7 +3,7 @@ name = "linkerd-cache"
 version = "0.1.0"
 authors = ["Linkerd Developers <cncf-linkerd-dev@lists.cncf.io>"]
 license = "Apache-2.0"
-edition = "2018"
+edition = "2021"
 publish = false
 
 [dependencies]
diff --git a/linkerd/conditional/Cargo.toml b/linkerd/conditional/Cargo.toml
index 0c1e892c74..6eb902949d 100644
--- a/linkerd/conditional/Cargo.toml
+++ b/linkerd/conditional/Cargo.toml
@@ -3,6 +3,6 @@ name = "linkerd-conditional"
 version = "0.1.0"
 authors = ["Linkerd Developers <cncf-linkerd-dev@lists.cncf.io>"]
 license = "Apache-2.0"
-edition = "2018"
+edition = "2021"
 
 [dependencies]
diff --git a/linkerd/detect/Cargo.toml b/linkerd/detect/Cargo.toml
index fe713f3f77..a0e06289ed 100644
--- a/linkerd/detect/Cargo.toml
+++ b/linkerd/detect/Cargo.toml
@@ -3,7 +3,7 @@ name = "linkerd-detect"
 version = "0.1.0"
 authors = ["Linkerd Developers <cncf-linkerd-dev@lists.cncf.io>"]
 license = "Apache-2.0"
-edition = "2018"
+edition = "2021"
 publish = false
 
 [dependencies]
diff --git a/linkerd/dns/Cargo.toml b/linkerd/dns/Cargo.toml
index ebe5670bdd..50d13cbec2 100644
--- a/linkerd/dns/Cargo.toml
+++ b/linkerd/dns/Cargo.toml
@@ -3,7 +3,7 @@ name = "linkerd-dns"
 version = "0.1.0"
 authors = ["Linkerd Developers <cncf-linkerd-dev@lists.cncf.io>"]
 license = "Apache-2.0"
-edition = "2018"
+edition = "2021"
 publish = false
 
 [dependencies]
diff --git a/linkerd/dns/fuzz/Cargo.toml b/linkerd/dns/fuzz/Cargo.toml
index 54a5402e6a..ba7c3b641e 100644
--- a/linkerd/dns/fuzz/Cargo.toml
+++ b/linkerd/dns/fuzz/Cargo.toml
@@ -4,7 +4,7 @@ name = "linkerd-dns-fuzz"
 version = "0.0.0"
 authors = ["Linkerd Developers <cncf-linkerd-dev@lists.cncf.io>"]
 publish = false
-edition = "2018"
+edition = "2021"
 
 [package.metadata]
 cargo-fuzz = true
diff --git a/linkerd/dns/name/Cargo.toml b/linkerd/dns/name/Cargo.toml
index 0a9bbb3c43..a45068f034 100644
--- a/linkerd/dns/name/Cargo.toml
+++ b/linkerd/dns/name/Cargo.toml
@@ -3,7 +3,7 @@ name = "linkerd-dns-name"
 version = "0.1.0"
 authors = ["Linkerd Developers <cncf-linkerd-dev@lists.cncf.io>"]
 license = "Apache-2.0"
-edition = "2018"
+edition = "2021"
 publish = false
 
 [dependencies]
diff --git a/linkerd/duplex/Cargo.toml b/linkerd/duplex/Cargo.toml
index 9e97573bb9..628de4d3ee 100644
--- a/linkerd/duplex/Cargo.toml
+++ b/linkerd/duplex/Cargo.toml
@@ -3,7 +3,7 @@ name = "linkerd-duplex"
 version = "0.1.0"
 authors = ["Linkerd Developers <cncf-linkerd-dev@lists.cncf.io>"]
 license = "Apache-2.0"
-edition = "2018"
+edition = "2021"
 publish = false
 
 [dependencies]
diff --git a/linkerd/errno/Cargo.toml b/linkerd/errno/Cargo.toml
index 7edc5d5dfd..3990cb47e1 100644
--- a/linkerd/errno/Cargo.toml
+++ b/linkerd/errno/Cargo.toml
@@ -3,5 +3,5 @@ name = "linkerd-errno"
 version = "0.1.0"
 authors = ["Linkerd Developers <cncf-linkerd-dev@lists.cncf.io>"]
 license = "Apache-2.0"
-edition = "2018"
+edition = "2021"
 publish = false
diff --git a/linkerd/error-respond/Cargo.toml b/linkerd/error-respond/Cargo.toml
index 8f3934924d..a2f6f8c26a 100644
--- a/linkerd/error-respond/Cargo.toml
+++ b/linkerd/error-respond/Cargo.toml
@@ -3,7 +3,7 @@ name = "linkerd-error-respond"
 version = "0.1.0"
 authors = ["Linkerd Developers <cncf-linkerd-dev@lists.cncf.io>"]
 license = "Apache-2.0"
-edition = "2018"
+edition = "2021"
 publish = false
 
 
diff --git a/linkerd/error/Cargo.toml b/linkerd/error/Cargo.toml
index 30e6e8ce0c..a556d848ce 100644
--- a/linkerd/error/Cargo.toml
+++ b/linkerd/error/Cargo.toml
@@ -3,7 +3,7 @@ name = "linkerd-error"
 version = "0.1.0"
 authors = ["Linkerd Developers <cncf-linkerd-dev@lists.cncf.io>"]
 license = "Apache-2.0"
-edition = "2018"
+edition = "2021"
 publish = false
 
 [dependencies]
diff --git a/linkerd/exp-backoff/Cargo.toml b/linkerd/exp-backoff/Cargo.toml
index 29497e4011..c332c83a20 100644
--- a/linkerd/exp-backoff/Cargo.toml
+++ b/linkerd/exp-backoff/Cargo.toml
@@ -3,7 +3,7 @@ name = "linkerd-exp-backoff"
 version = "0.1.0"
 authors = ["Linkerd Developers <cncf-linkerd-dev@lists.cncf.io>"]
 license = "Apache-2.0"
-edition = "2018"
+edition = "2021"
 publish = false
 
 
diff --git a/linkerd/http-box/Cargo.toml b/linkerd/http-box/Cargo.toml
index 079bbf2bbc..d844a1f675 100644
--- a/linkerd/http-box/Cargo.toml
+++ b/linkerd/http-box/Cargo.toml
@@ -3,7 +3,7 @@ name = "linkerd-http-box"
 version = "0.1.0"
 authors = ["Linkerd Developers <cncf-linkerd-dev@lists.cncf.io>"]
 license = "Apache-2.0"
-edition = "2018"
+edition = "2021"
 publish = false
 
 [dependencies]
diff --git a/linkerd/http-classify/Cargo.toml b/linkerd/http-classify/Cargo.toml
index bcc2c8094d..0cb4fd038f 100644
--- a/linkerd/http-classify/Cargo.toml
+++ b/linkerd/http-classify/Cargo.toml
@@ -3,7 +3,7 @@ name = "linkerd-http-classify"
 version = "0.1.0"
 authors = ["Linkerd Developers <cncf-linkerd-dev@lists.cncf.io>"]
 license = "Apache-2.0"
-edition = "2018"
+edition = "2021"
 publish = false
 
 [dependencies]
diff --git a/linkerd/http-metrics/Cargo.toml b/linkerd/http-metrics/Cargo.toml
index 2f07ff6bb4..f5f5b454f3 100644
--- a/linkerd/http-metrics/Cargo.toml
+++ b/linkerd/http-metrics/Cargo.toml
@@ -3,7 +3,7 @@ name = "linkerd-http-metrics"
 version = "0.1.0"
 authors = ["Linkerd Developers <cncf-linkerd-dev@lists.cncf.io>"]
 license = "Apache-2.0"
-edition = "2018"
+edition = "2021"
 publish = false
 
 [dependencies]
diff --git a/linkerd/http-metrics/src/requests/mod.rs b/linkerd/http-metrics/src/requests.rs
similarity index 100%
rename from linkerd/http-metrics/src/requests/mod.rs
rename to linkerd/http-metrics/src/requests.rs
diff --git a/linkerd/http-retry/Cargo.toml b/linkerd/http-retry/Cargo.toml
index 6b219908ba..6d11692799 100644
--- a/linkerd/http-retry/Cargo.toml
+++ b/linkerd/http-retry/Cargo.toml
@@ -3,7 +3,7 @@ name = "linkerd-http-retry"
 version = "0.1.0"
 authors = ["Linkerd Developers <cncf-linkerd-dev@lists.cncf.io>"]
 license = "Apache-2.0"
-edition = "2018"
+edition = "2021"
 publish = false
 
 [dependencies]
diff --git a/linkerd/identity/Cargo.toml b/linkerd/identity/Cargo.toml
index 5ae5915822..812629bdb1 100644
--- a/linkerd/identity/Cargo.toml
+++ b/linkerd/identity/Cargo.toml
@@ -3,7 +3,7 @@ name = "linkerd-identity"
 version = "0.1.0"
 authors = ["Linkerd Developers <cncf-linkerd-dev@lists.cncf.io>"]
 license = "Apache-2.0"
-edition = "2018"
+edition = "2021"
 publish = false
 
 [dependencies]
diff --git a/linkerd/io/Cargo.toml b/linkerd/io/Cargo.toml
index 4e9ab36fa1..5ac52ff8d9 100644
--- a/linkerd/io/Cargo.toml
+++ b/linkerd/io/Cargo.toml
@@ -3,7 +3,7 @@ name = "linkerd-io"
 version = "0.1.0"
 authors = ["Linkerd Developers <cncf-linkerd-dev@lists.cncf.io>"]
 license = "Apache-2.0"
-edition = "2018"
+edition = "2021"
 publish = false
 description = """
 General I/O primitives.
diff --git a/linkerd/metrics/Cargo.toml b/linkerd/metrics/Cargo.toml
index 4ea291e327..8497ec88cf 100644
--- a/linkerd/metrics/Cargo.toml
+++ b/linkerd/metrics/Cargo.toml
@@ -3,7 +3,7 @@ name = "linkerd-metrics"
 version = "0.1.0"
 authors = ["Linkerd Developers <cncf-linkerd-dev@lists.cncf.io>"]
 license = "Apache-2.0"
-edition = "2018"
+edition = "2021"
 publish = false
 
 [features]
diff --git a/linkerd/metrics/src/latency.rs b/linkerd/metrics/src/latency.rs
index 49788fe94c..23b6bde595 100644
--- a/linkerd/metrics/src/latency.rs
+++ b/linkerd/metrics/src/latency.rs
@@ -44,7 +44,6 @@ pub struct Us(Duration);
 
 impl From<Us> for u64 {
     fn from(Us(us): Us) -> u64 {
-        use std::convert::TryInto;
         us.as_micros().try_into().unwrap_or_else(|_| {
             // These measurements should never be long enough to overflow
             tracing::warn!("Duration::as_micros would overflow u64");
diff --git a/linkerd/opencensus/Cargo.toml b/linkerd/opencensus/Cargo.toml
index 2775e8a9c5..3632d52d44 100644
--- a/linkerd/opencensus/Cargo.toml
+++ b/linkerd/opencensus/Cargo.toml
@@ -3,7 +3,7 @@ name = "linkerd-opencensus"
 version = "0.1.0"
 authors = ["Linkerd Developers <cncf-linkerd-dev@lists.cncf.io>"]
 license = "Apache-2.0"
-edition = "2018"
+edition = "2021"
 publish = false
 
 [dependencies]
diff --git a/linkerd/proxy/api-resolve/Cargo.toml b/linkerd/proxy/api-resolve/Cargo.toml
index 641792387e..78928dc942 100644
--- a/linkerd/proxy/api-resolve/Cargo.toml
+++ b/linkerd/proxy/api-resolve/Cargo.toml
@@ -3,7 +3,7 @@ name = "linkerd-proxy-api-resolve"
 version = "0.1.0"
 authors = ["Linkerd Developers <cncf-linkerd-dev@lists.cncf.io>"]
 license = "Apache-2.0"
-edition = "2018"
+edition = "2021"
 publish = false
 description = """
 Implements the Resolve trait using the proxy's gRPC API
diff --git a/linkerd/proxy/core/Cargo.toml b/linkerd/proxy/core/Cargo.toml
index 9e39d241c4..9be75cb857 100644
--- a/linkerd/proxy/core/Cargo.toml
+++ b/linkerd/proxy/core/Cargo.toml
@@ -3,7 +3,7 @@ name = "linkerd-proxy-core"
 version = "0.1.0"
 authors = ["Linkerd Developers <cncf-linkerd-dev@lists.cncf.io>"]
 license = "Apache-2.0"
-edition = "2018"
+edition = "2021"
 publish = false
 description = """
 Core interfaces needed to implement proxy components
diff --git a/linkerd/proxy/discover/Cargo.toml b/linkerd/proxy/discover/Cargo.toml
index 2d8a7045a1..e298527e71 100644
--- a/linkerd/proxy/discover/Cargo.toml
+++ b/linkerd/proxy/discover/Cargo.toml
@@ -3,7 +3,7 @@ name = "linkerd-proxy-discover"
 version = "0.1.0"
 authors = ["Linkerd Developers <cncf-linkerd-dev@lists.cncf.io>"]
 license = "Apache-2.0"
-edition = "2018"
+edition = "2021"
 publish = false
 description = """
 Utilities to implement a Discover with the core Resolve type
diff --git a/linkerd/proxy/dns-resolve/Cargo.toml b/linkerd/proxy/dns-resolve/Cargo.toml
index 92ac0a5c11..7e7df97eb0 100644
--- a/linkerd/proxy/dns-resolve/Cargo.toml
+++ b/linkerd/proxy/dns-resolve/Cargo.toml
@@ -3,7 +3,7 @@ name = "linkerd-proxy-dns-resolve"
 version = "0.1.0"
 authors = ["Linkerd Developers <cncf-linkerd-dev@lists.cncf.io>"]
 license = "Apache-2.0"
-edition = "2018"
+edition = "2021"
 publish = false
 description = """
 Service Dns Resolutions for the proxy
diff --git a/linkerd/proxy/http/Cargo.toml b/linkerd/proxy/http/Cargo.toml
index a297a0cfcb..77844577a5 100644
--- a/linkerd/proxy/http/Cargo.toml
+++ b/linkerd/proxy/http/Cargo.toml
@@ -3,7 +3,7 @@ name = "linkerd-proxy-http"
 version = "0.1.0"
 authors = ["Linkerd Developers <cncf-linkerd-dev@lists.cncf.io>"]
 license = "Apache-2.0"
-edition = "2018"
+edition = "2021"
 publish = false
 description = """
 HTTP-specific implementations that rely on other proxy infrastructure
diff --git a/linkerd/proxy/http/fuzz/Cargo.toml b/linkerd/proxy/http/fuzz/Cargo.toml
index d9ae834f2d..d7970588e8 100644
--- a/linkerd/proxy/http/fuzz/Cargo.toml
+++ b/linkerd/proxy/http/fuzz/Cargo.toml
@@ -4,7 +4,7 @@ name = "linkerd-proxy-http-fuzz"
 version = "0.0.0"
 authors = ["Linkerd Developers <cncf-linkerd-dev@lists.cncf.io>"]
 publish = false
-edition = "2018"
+edition = "2021"
 
 [package.metadata]
 cargo-fuzz = true
diff --git a/linkerd/proxy/identity/Cargo.toml b/linkerd/proxy/identity/Cargo.toml
index 92770b88bc..703360c992 100644
--- a/linkerd/proxy/identity/Cargo.toml
+++ b/linkerd/proxy/identity/Cargo.toml
@@ -3,7 +3,7 @@ name = "linkerd-proxy-identity"
 version = "0.1.0"
 authors = ["Linkerd Developers <cncf-linkerd-dev@lists.cncf.io>"]
 license = "Apache-2.0"
-edition = "2018"
+edition = "2021"
 publish = false
 
 [features]
diff --git a/linkerd/proxy/resolve/Cargo.toml b/linkerd/proxy/resolve/Cargo.toml
index 510c4cb2ea..dcea487e0e 100644
--- a/linkerd/proxy/resolve/Cargo.toml
+++ b/linkerd/proxy/resolve/Cargo.toml
@@ -3,7 +3,7 @@ name = "linkerd-proxy-resolve"
 version = "0.1.0"
 authors = ["Linkerd Developers <cncf-linkerd-dev@lists.cncf.io>"]
 license = "Apache-2.0"
-edition = "2018"
+edition = "2021"
 publish = false
 description = """
 Utilities for working with `Resolve` implementations
diff --git a/linkerd/proxy/tap/Cargo.toml b/linkerd/proxy/tap/Cargo.toml
index d64daa6444..dccaf07a59 100644
--- a/linkerd/proxy/tap/Cargo.toml
+++ b/linkerd/proxy/tap/Cargo.toml
@@ -3,7 +3,7 @@ name = "linkerd-proxy-tap"
 version = "0.1.0"
 authors = ["Linkerd Developers <cncf-linkerd-dev@lists.cncf.io>"]
 license = "Apache-2.0"
-edition = "2018"
+edition = "2021"
 publish = false
 
 [features]
diff --git a/linkerd/proxy/tap/src/grpc/mod.rs b/linkerd/proxy/tap/src/grpc.rs
similarity index 100%
rename from linkerd/proxy/tap/src/grpc/mod.rs
rename to linkerd/proxy/tap/src/grpc.rs
diff --git a/linkerd/proxy/tap/src/grpc/match_.rs b/linkerd/proxy/tap/src/grpc/match_.rs
index b2e4d65eeb..bbeac44c45 100644
--- a/linkerd/proxy/tap/src/grpc/match_.rs
+++ b/linkerd/proxy/tap/src/grpc/match_.rs
@@ -2,13 +2,7 @@ use crate::Inspect;
 use ipnet::{Ipv4Net, Ipv6Net};
 use linkerd2_proxy_api::net::ip_address;
 use linkerd2_proxy_api::tap::observe_request;
-use std::{
-    boxed::Box,
-    collections::BTreeMap,
-    convert::{TryFrom, TryInto},
-    net,
-    str::FromStr,
-};
+use std::{boxed::Box, collections::BTreeMap, net, str::FromStr};
 use thiserror::Error;
 
 #[derive(Clone, Debug)]
diff --git a/linkerd/proxy/tcp/Cargo.toml b/linkerd/proxy/tcp/Cargo.toml
index 27f2196561..4979d9d891 100644
--- a/linkerd/proxy/tcp/Cargo.toml
+++ b/linkerd/proxy/tcp/Cargo.toml
@@ -3,7 +3,7 @@ name = "linkerd-proxy-tcp"
 version = "0.1.0"
 authors = ["Linkerd Developers <cncf-linkerd-dev@lists.cncf.io>"]
 license = "Apache-2.0"
-edition = "2018"
+edition = "2021"
 publish = false
 
 
diff --git a/linkerd/proxy/transport/Cargo.toml b/linkerd/proxy/transport/Cargo.toml
index 245470384d..a9fe5f409a 100644
--- a/linkerd/proxy/transport/Cargo.toml
+++ b/linkerd/proxy/transport/Cargo.toml
@@ -3,7 +3,7 @@ name = "linkerd-proxy-transport"
 version = "0.1.0"
 authors = ["Linkerd Developers <cncf-linkerd-dev@lists.cncf.io>"]
 license = "Apache-2.0"
-edition = "2018"
+edition = "2021"
 publish = false
 description = """
 Transport-level implementations that rely on core proxy infrastructure
diff --git a/linkerd/reconnect/Cargo.toml b/linkerd/reconnect/Cargo.toml
index 934efed7c2..3a0c6b0e5d 100644
--- a/linkerd/reconnect/Cargo.toml
+++ b/linkerd/reconnect/Cargo.toml
@@ -3,7 +3,7 @@ name = "linkerd-reconnect"
 version = "0.1.0"
 authors = ["Linkerd Developers <cncf-linkerd-dev@lists.cncf.io>"]
 license = "Apache-2.0"
-edition = "2018"
+edition = "2021"
 publish = false
 
 [dependencies]
diff --git a/linkerd/retry/Cargo.toml b/linkerd/retry/Cargo.toml
index 3d8af52e1b..792b8cb75c 100644
--- a/linkerd/retry/Cargo.toml
+++ b/linkerd/retry/Cargo.toml
@@ -3,7 +3,7 @@ name = "linkerd-retry"
 version = "0.1.0"
 authors = ["Linkerd Developers <cncf-linkerd-dev@lists.cncf.io>"]
 license = "Apache-2.0"
-edition = "2018"
+edition = "2021"
 publish = false
 
 [dependencies]
diff --git a/linkerd/server-policy/Cargo.toml b/linkerd/server-policy/Cargo.toml
index 14fc0e91b6..42f78b0f7e 100644
--- a/linkerd/server-policy/Cargo.toml
+++ b/linkerd/server-policy/Cargo.toml
@@ -3,7 +3,7 @@ name = "linkerd-server-policy"
 version = "0.1.0"
 authors = ["Linkerd Developers <cncf-linkerd-dev@lists.cncf.io>"]
 license = "Apache-2.0"
-edition = "2018"
+edition = "2021"
 publish = false
 
 [dependencies]
diff --git a/linkerd/service-profiles/Cargo.toml b/linkerd/service-profiles/Cargo.toml
index 7b84a241da..d25fe1fbdb 100644
--- a/linkerd/service-profiles/Cargo.toml
+++ b/linkerd/service-profiles/Cargo.toml
@@ -3,7 +3,7 @@ name = "linkerd-service-profiles"
 version = "0.1.0"
 authors = ["Linkerd Developers <cncf-linkerd-dev@lists.cncf.io>"]
 license = "Apache-2.0"
-edition = "2018"
+edition = "2021"
 publish = false
 description = """
 Implements client layers for Linkerd ServiceProfiles.
diff --git a/linkerd/service-profiles/src/http/mod.rs b/linkerd/service-profiles/src/http.rs
similarity index 100%
rename from linkerd/service-profiles/src/http/mod.rs
rename to linkerd/service-profiles/src/http.rs
diff --git a/linkerd/service-profiles/src/proto.rs b/linkerd/service-profiles/src/proto.rs
index 99f1572da6..d0c82b416a 100644
--- a/linkerd/service-profiles/src/proto.rs
+++ b/linkerd/service-profiles/src/proto.rs
@@ -4,7 +4,7 @@ use linkerd_addr::NameAddr;
 use linkerd_dns_name::Name;
 use linkerd_proxy_api_resolve::pb as resolve;
 use regex::Regex;
-use std::{convert::TryInto, str::FromStr, sync::Arc, time::Duration};
+use std::{str::FromStr, sync::Arc, time::Duration};
 use tower::retry::budget::Budget;
 use tracing::warn;
 
diff --git a/linkerd/signal/Cargo.toml b/linkerd/signal/Cargo.toml
index a74ab722db..fac604deb8 100644
--- a/linkerd/signal/Cargo.toml
+++ b/linkerd/signal/Cargo.toml
@@ -3,7 +3,7 @@ name = "linkerd-signal"
 version = "0.1.0"
 authors = ["Linkerd Developers <cncf-linkerd-dev@lists.cncf.io>"]
 license = "Apache-2.0"
-edition = "2018"
+edition = "2021"
 publish = false
 
 [dependencies]
diff --git a/linkerd/stack/Cargo.toml b/linkerd/stack/Cargo.toml
index c6157aa406..8d31ab517f 100644
--- a/linkerd/stack/Cargo.toml
+++ b/linkerd/stack/Cargo.toml
@@ -3,7 +3,7 @@ name = "linkerd-stack"
 version = "0.1.0"
 authors = ["Linkerd Developers <cncf-linkerd-dev@lists.cncf.io>"]
 license = "Apache-2.0"
-edition = "2018"
+edition = "2021"
 publish = false
 description = """
 Utilities for composing Tower services.
diff --git a/linkerd/stack/metrics/Cargo.toml b/linkerd/stack/metrics/Cargo.toml
index 93fc575fc8..2bc00530d2 100644
--- a/linkerd/stack/metrics/Cargo.toml
+++ b/linkerd/stack/metrics/Cargo.toml
@@ -3,7 +3,7 @@ name = "linkerd-stack-metrics"
 version = "0.1.0"
 authors = ["Linkerd Developers <cncf-linkerd-dev@lists.cncf.io>"]
 license = "Apache-2.0"
-edition = "2018"
+edition = "2021"
 publish = false
 
 [dependencies]
diff --git a/linkerd/stack/tracing/Cargo.toml b/linkerd/stack/tracing/Cargo.toml
index d4b5fcbf68..3ba457b4b8 100644
--- a/linkerd/stack/tracing/Cargo.toml
+++ b/linkerd/stack/tracing/Cargo.toml
@@ -3,7 +3,7 @@ name = "linkerd-stack-tracing"
 version = "0.1.0"
 authors = ["Linkerd Developers <cncf-linkerd-dev@lists.cncf.io>"]
 license = "Apache-2.0"
-edition = "2018"
+edition = "2021"
 publish = false
 
 [dependencies]
diff --git a/linkerd/system/Cargo.toml b/linkerd/system/Cargo.toml
index 1d0c2dff37..4692de68f2 100644
--- a/linkerd/system/Cargo.toml
+++ b/linkerd/system/Cargo.toml
@@ -3,7 +3,7 @@ name = "linkerd-system"
 version = "0.1.0"
 authors = ["Linkerd Developers <cncf-linkerd-dev@lists.cncf.io>"]
 license = "Apache-2.0"
-edition = "2018"
+edition = "2021"
 publish = false
 description = """
 Unsafe code for accessing system-level counters for memory & CPU usage.
diff --git a/linkerd/tls/Cargo.toml b/linkerd/tls/Cargo.toml
index 2ef68a3506..e7ade011c8 100644
--- a/linkerd/tls/Cargo.toml
+++ b/linkerd/tls/Cargo.toml
@@ -3,7 +3,7 @@ name = "linkerd-tls"
 version = "0.1.0"
 authors = ["Linkerd Developers <cncf-linkerd-dev@lists.cncf.io>"]
 license = "Apache-2.0"
-edition = "2018"
+edition = "2021"
 publish = false
 
 [dependencies]
diff --git a/linkerd/tls/fuzz/Cargo.toml b/linkerd/tls/fuzz/Cargo.toml
index 23ff35bba4..2ad7dad215 100644
--- a/linkerd/tls/fuzz/Cargo.toml
+++ b/linkerd/tls/fuzz/Cargo.toml
@@ -4,7 +4,7 @@ name = "linkerd-tls-fuzz"
 version = "0.0.0"
 authors = ["Linkerd Developers <cncf-linkerd-dev@lists.cncf.io>"]
 publish = false
-edition = "2018"
+edition = "2021"
 
 [package.metadata]
 cargo-fuzz = true
diff --git a/linkerd/tls/src/server/mod.rs b/linkerd/tls/src/server.rs
similarity index 98%
rename from linkerd/tls/src/server/mod.rs
rename to linkerd/tls/src/server.rs
index b82c79d31a..57e66aea5c 100644
--- a/linkerd/tls/src/server/mod.rs
+++ b/linkerd/tls/src/server.rs
@@ -306,13 +306,13 @@ mod tests {
         let _trace = linkerd_tracing::test::trace_init();
 
         let (mut client_io, server_io) = tokio::io::duplex(1024);
-        let input = include_bytes!("testdata/curl-example-com-client-hello.bin");
+        let input = include_bytes!("server/testdata/curl-example-com-client-hello.bin");
         let len = input.len();
         let client_task = tokio::spawn(async move {
             client_io
                 .write_all(&*input)
                 .await
-                .expect("Write must suceed");
+                .expect("Write must succeed");
         });
 
         let (sni, io) = detect_sni(server_io)
diff --git a/linkerd/tonic-watch/Cargo.toml b/linkerd/tonic-watch/Cargo.toml
index 0dfcfcf54a..c9a5e37010 100644
--- a/linkerd/tonic-watch/Cargo.toml
+++ b/linkerd/tonic-watch/Cargo.toml
@@ -3,7 +3,7 @@ name = "linkerd-tonic-watch"
 version = "0.1.0"
 authors = ["Linkerd Developers <cncf-linkerd-dev@lists.cncf.io>"]
 license = "Apache-2.0"
-edition = "2018"
+edition = "2021"
 publish = false
 description = """
 Provides a utility for creating robust watches from a service that returns a stream.
diff --git a/linkerd/trace-context/Cargo.toml b/linkerd/trace-context/Cargo.toml
index 0034308431..a8304484d8 100644
--- a/linkerd/trace-context/Cargo.toml
+++ b/linkerd/trace-context/Cargo.toml
@@ -3,7 +3,7 @@ name = "linkerd-trace-context"
 version = "0.1.0"
 authors = ["Linkerd Developers <cncf-linkerd-dev@lists.cncf.io>"]
 license = "Apache-2.0"
-edition = "2018"
+edition = "2021"
 publish = false
 
 [dependencies]
diff --git a/linkerd/trace-context/src/propagation.rs b/linkerd/trace-context/src/propagation.rs
index dc4c0894b9..042ff3562e 100644
--- a/linkerd/trace-context/src/propagation.rs
+++ b/linkerd/trace-context/src/propagation.rs
@@ -3,7 +3,6 @@ use bytes::Bytes;
 use http::header::HeaderValue;
 use linkerd_error::Error;
 use rand::thread_rng;
-use std::convert::TryInto;
 use thiserror::Error;
 use tracing::{trace, warn};
 
diff --git a/linkerd/tracing/Cargo.toml b/linkerd/tracing/Cargo.toml
index 80b4bb64b9..143919c146 100644
--- a/linkerd/tracing/Cargo.toml
+++ b/linkerd/tracing/Cargo.toml
@@ -3,7 +3,7 @@ name = "linkerd-tracing"
 version = "0.1.0"
 authors = ["Linkerd Developers <cncf-linkerd-dev@lists.cncf.io>"]
 license = "Apache-2.0"
-edition = "2018"
+edition = "2021"
 publish = false
 
 [features]
diff --git a/linkerd/transport-header/Cargo.toml b/linkerd/transport-header/Cargo.toml
index c36b7a0d8d..040ca8e13b 100644
--- a/linkerd/transport-header/Cargo.toml
+++ b/linkerd/transport-header/Cargo.toml
@@ -3,7 +3,7 @@ name = "linkerd-transport-header"
 version = "0.1.0"
 authors = ["Linkerd Developers <cncf-linkerd-dev@lists.cncf.io>"]
 license = "Apache-2.0"
-edition = "2018"
+edition = "2021"
 publish = false
 
 [dependencies]
diff --git a/linkerd/transport-header/fuzz/Cargo.toml b/linkerd/transport-header/fuzz/Cargo.toml
index f1bd76a966..d78ab8421d 100644
--- a/linkerd/transport-header/fuzz/Cargo.toml
+++ b/linkerd/transport-header/fuzz/Cargo.toml
@@ -3,7 +3,7 @@ name = "linkerd-transport-header-fuzz"
 version = "0.0.0"
 authors = ["Linkerd Developers <cncf-linkerd-dev@lists.cncf.io>"]
 publish = false
-edition = "2018"
+edition = "2021"
 
 [package.metadata]
 cargo-fuzz = true
diff --git a/linkerd/transport-metrics/Cargo.toml b/linkerd/transport-metrics/Cargo.toml
index 3a8d7f26c5..3a18433874 100644
--- a/linkerd/transport-metrics/Cargo.toml
+++ b/linkerd/transport-metrics/Cargo.toml
@@ -3,7 +3,7 @@ name = "linkerd-transport-metrics"
 version = "0.1.0"
 authors = ["Linkerd Developers <cncf-linkerd-dev@lists.cncf.io>"]
 license = "Apache-2.0"
-edition = "2018"
+edition = "2021"
 publish = false
 description = """Transport-level metrics"""
 
diff --git a/linkerd2-proxy/Cargo.toml b/linkerd2-proxy/Cargo.toml
index f8007510af..b34d390403 100644
--- a/linkerd2-proxy/Cargo.toml
+++ b/linkerd2-proxy/Cargo.toml
@@ -3,7 +3,7 @@ name = "linkerd2-proxy"
 version = "0.1.0"
 authors = ["Linkerd Developers <cncf-linkerd-dev@lists.cncf.io>"]
 license = "Apache-2.0"
-edition = "2018"
+edition = "2021"
 publish = false
 description = "The main proxy executable"
 
diff --git a/opencensus-proto/Cargo.toml b/opencensus-proto/Cargo.toml
index c5ff0f3db4..27c03b03bc 100644
--- a/opencensus-proto/Cargo.toml
+++ b/opencensus-proto/Cargo.toml
@@ -3,7 +3,7 @@ name = "opencensus-proto"
 version = "0.1.0"
 authors = ["The OpenCensus Authors"]
 license = "Apache-2.0"
-edition = "2018"
+edition = "2021"
 publish = false
 description = """
 gRPC bindings for OpenCensus.
diff --git a/rust-toolchain b/rust-toolchain
index 094d6ad00c..3ebf789f5a 100644
--- a/rust-toolchain
+++ b/rust-toolchain
@@ -1 +1 @@
-1.55.0
+1.56.0