diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 7c4126c201..bf6fbb65eb 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -9,7 +9,7 @@ on:
 env:
   CARGO_TERM_COLOR: always
   GO_VERSION: '1.21'
-  ACTION_MSRV_TOOLCHAIN: 1.75.0
+  ACTION_MSRV_TOOLCHAIN: 1.66.1
   NIX_VERSION: '2.21.0'
 jobs:
   build:
diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index 1469713fcd..048789ebe7 100644
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -8,7 +8,7 @@ on:
 env:
   CARGO_TERM_COLOR: always
   GO_VERSION: '1.21'
-  ACTION_MSRV_TOOLCHAIN: 1.75.0
+  ACTION_MSRV_TOOLCHAIN: 1.66.1
 
 jobs:
   build:
diff --git a/Cargo.lock b/Cargo.lock
index 879fb405ce..2e68d73579 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -52,9 +52,9 @@ dependencies = [
 
 [[package]]
 name = "anstyle"
-version = "1.0.6"
+version = "1.0.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8901269c6307e8d93993578286ac0edf7f195079ffff5ebdeea6a59ffb7e36bc"
+checksum = "15c4c2c83f81532e5845a733998b6971faca23490340a418e9b72a3ec9de12ea"
 
 [[package]]
 name = "anstyle-parse"
@@ -284,17 +284,11 @@ version = "1.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "baf1de4339761588bc0619e3cbc0120ee582ebb74b53b4efbf79117bd2da40fd"
 
-[[package]]
-name = "cfg_aliases"
-version = "0.1.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "fd16c4719339c4530435d38e511904438d07cce7950afa3718a84ac36c10e89e"
-
 [[package]]
 name = "clap"
-version = "4.3.8"
+version = "4.3.24"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d9394150f5b4273a1763355bd1c2ec54cc5a2593f790587bcd6b2c947cfa9211"
+checksum = "fb690e81c7840c0d7aade59f242ea3b41b9bc27bcd5997890e7702ae4b32e487"
 dependencies = [
  "clap_builder",
  "clap_derive",
@@ -303,13 +297,12 @@ dependencies = [
 
 [[package]]
 name = "clap_builder"
-version = "4.3.8"
+version = "4.3.24"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "9a78fbdd3cc2914ddf37ba444114bc7765bbdcb55ec9cbe6fa054f0137400717"
+checksum = "5ed2e96bc16d8d740f6f48d663eddf4b8a0983e79210fd55479b7bcd0a69860e"
 dependencies = [
  "anstream",
  "anstyle",
- "bitflags 1.3.2",
  "clap_lex",
  "once_cell",
  "strsim",
@@ -320,9 +313,9 @@ dependencies = [
 
 [[package]]
 name = "clap_derive"
-version = "4.3.2"
+version = "4.3.12"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b8cd2b2a819ad6eec39e8f1d6b53001af1e5469f8c177579cdaeb313115b825f"
+checksum = "54a9bb5758fc5dfe728d1019941681eccaf0cf8a4189b692a0ee2f2ecf90a050"
 dependencies = [
  "heck",
  "proc-macro2",
@@ -348,7 +341,7 @@ version = "0.3.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "7bb11bd1378bf3731b182997b40cefe00aba6a6cc74042c8318c1b271d3badf7"
 dependencies = [
- "nix 0.27.1",
+ "nix",
  "thiserror",
  "tokio",
 ]
@@ -380,7 +373,7 @@ dependencies = [
  "memchr",
  "mockall",
  "multimap",
- "nix 0.28.0",
+ "nix",
  "notify",
  "once_cell",
  "opentelemetry",
@@ -501,15 +494,6 @@ dependencies = [
  "parking_lot_core",
 ]
 
-[[package]]
-name = "deranged"
-version = "0.3.11"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b42b6fa04a440b495c8b04d0e71b707c585f83cb9cb28cf8cd0d976c315e31b4"
-dependencies = [
- "powerfmt",
-]
-
 [[package]]
 name = "digest"
 version = "0.10.7"
@@ -1017,9 +1001,9 @@ checksum = "06d198e9919d9822d5f7083ba8530e04de87841eaf21ead9af8f2304efd57c89"
 
 [[package]]
 name = "itertools"
-version = "0.12.1"
+version = "0.11.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ba291022dbbd398a455acf126c1e341954079855bc60dfdda641363bd6922569"
+checksum = "b1c173a5686ce8bfa551b3563d0c2170bf24ca44da99c7ca4bfdab5418c3fe57"
 dependencies = [
  "either",
 ]
@@ -1101,7 +1085,7 @@ dependencies = [
  "hmac",
  "libc",
  "log",
- "nix 0.27.1",
+ "nix",
  "nom",
  "once_cell",
  "serde",
@@ -1255,19 +1239,6 @@ dependencies = [
  "memoffset",
 ]
 
-[[package]]
-name = "nix"
-version = "0.28.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ab2156c4fce2f8df6c499cc1c763e4394b7482525bf2a9701c9d79d215f519e4"
-dependencies = [
- "bitflags 2.4.1",
- "cfg-if",
- "cfg_aliases",
- "libc",
- "memoffset",
-]
-
 [[package]]
 name = "nom"
 version = "7.1.3"
@@ -1307,12 +1278,6 @@ dependencies = [
  "winapi",
 ]
 
-[[package]]
-name = "num-conv"
-version = "0.1.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "51d515d32fb182ee37cda2ccdcb92950d6a3c2893aa280e540671c2cd0f3b1d9"
-
 [[package]]
 name = "num-traits"
 version = "0.2.18"
@@ -1508,12 +1473,6 @@ version = "0.3.30"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "d231b230927b5e4ad203db57bbcbee2802f6bce620b1e4a9024a07d94e2907ec"
 
-[[package]]
-name = "powerfmt"
-version = "0.2.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "439ee305def115ba05938db6eb1644ff94165c5ab5e9420d1c1bcedbba909391"
-
 [[package]]
 name = "ppv-lite86"
 version = "0.2.17"
@@ -1527,7 +1486,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "059a34f111a9dee2ce1ac2826a68b24601c4298cfeb1a587c3cb493d5ab46f52"
 dependencies = [
  "libc",
- "nix 0.28.0",
+ "nix",
 ]
 
 [[package]]
@@ -1591,9 +1550,9 @@ dependencies = [
 
 [[package]]
 name = "prost"
-version = "0.12.4"
+version = "0.12.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d0f5d036824e4761737860779c906171497f6d55681139d8312388f8fe398922"
+checksum = "146c289cda302b98a28d40c8b3b90498d6e526dd24ac2ecea73e4e491685b94a"
 dependencies = [
  "bytes",
  "prost-derive",
@@ -1601,9 +1560,9 @@ dependencies = [
 
 [[package]]
 name = "prost-derive"
-version = "0.12.4"
+version = "0.12.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "19de2de2a00075bf566bee3bd4db014b11587e84184d3f7a791bc17f1a8e9e48"
+checksum = "efb6c9a1dd1def8e2124d17e83a20af56f1570d6c2d2bd9e266ccb768df3840e"
 dependencies = [
  "anyhow",
  "itertools",
@@ -1989,16 +1948,13 @@ dependencies = [
 
 [[package]]
 name = "time"
-version = "0.3.36"
+version = "0.3.23"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "5dfd88e563464686c916c7e46e623e520ddc6d79fa6641390f2e3fa86e83e885"
+checksum = "59e399c068f43a5d116fedaf73b203fa4f9c519f17e2b34f63221d3792f81446"
 dependencies = [
- "deranged",
  "itoa",
  "libc",
- "num-conv",
  "num_threads",
- "powerfmt",
  "serde",
  "time-core",
  "time-macros",
@@ -2006,17 +1962,16 @@ dependencies = [
 
 [[package]]
 name = "time-core"
-version = "0.1.2"
+version = "0.1.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ef927ca75afb808a4d64dd374f00a2adf8d0fcff8e7b184af886c3c87ec4a3f3"
+checksum = "7300fbefb4dadc1af235a9cef3737cea692a9d97e1b9cbcd4ebdae6f8868e6fb"
 
 [[package]]
 name = "time-macros"
-version = "0.2.18"
+version = "0.2.10"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3f252a68540fde3a3877aeea552b832b40ab9a69e318efd078774a01ddee1ccf"
+checksum = "96ba15a897f3c86766b757e5ac7221554c6750054d74d5b28844fce5fb36a6c4"
 dependencies = [
- "num-conv",
  "time-core",
 ]
 
diff --git a/conmon-rs/server/Cargo.toml b/conmon-rs/server/Cargo.toml
index 35038db9bb..511f164b04 100644
--- a/conmon-rs/server/Cargo.toml
+++ b/conmon-rs/server/Cargo.toml
@@ -11,7 +11,7 @@ path = "src/main.rs"
 anyhow = "1.0.82"
 capnp = "0.19.3"
 capnp-rpc = "0.19.0"
-clap = { version = "4.3.8", features = ["color", "cargo", "deprecated", "derive", "deprecated", "env", "string", "unicode", "wrap_help"] }
+clap = { version = "=4.3.24", features = ["color", "cargo", "deprecated", "derive", "deprecated", "env", "string", "unicode", "wrap_help"] }
 command-fds = { version = "0.3.0", features = ["tokio"] }
 conmon-common = { path = "../common" }
 futures = "0.3.30"
@@ -21,7 +21,7 @@ libc = "0.2.153"
 libsystemd = "0.7.0"
 memchr = "2.7.2"
 multimap = "0.10.0"
-nix = { version = "0.28.0", features = ["fs", "hostname", "mount", "sched", "signal", "socket", "term", "user"] }
+nix = { version = "=0.27.1", features = ["fs", "hostname", "mount", "sched", "signal", "socket", "term", "user"] }
 notify = "6.1.1"
 once_cell = "1.19.0"
 opentelemetry = "0.22.0"
@@ -53,4 +53,4 @@ dashmap = "5.5.3"
 
 [dev-dependencies]
 mockall = "0.12.1"
-time = { version = "0.3.36", features = ["parsing"] }
+time = { version = "=0.3.23", features = ["parsing"] }
diff --git a/conmon-rs/server/src/attach.rs b/conmon-rs/server/src/attach.rs
index bc048551cf..72295c8944 100644
--- a/conmon-rs/server/src/attach.rs
+++ b/conmon-rs/server/src/attach.rs
@@ -5,7 +5,7 @@ use crate::{
 use anyhow::{bail, Context, Result};
 use nix::{
     errno::Errno,
-    sys::socket::{bind, listen, socket, AddressFamily, Backlog, SockFlag, SockType, UnixAddr},
+    sys::socket::{bind, listen, socket, AddressFamily, SockFlag, SockType, UnixAddr},
 };
 use std::{
     os::{
@@ -158,7 +158,7 @@ impl Attach {
         let mut permissions = metadata.permissions();
         permissions.set_mode(0o700);
 
-        listen(&fd, Backlog::new(10).context("create backlog")?).context("listen on socket fd")?;
+        listen(&fd, 10).context("listen on socket fd")?;
 
         task::spawn(
             async move {
@@ -246,7 +246,7 @@ impl Attach {
                             debug!("Read {} stdin bytes from client", buf.len());
                             tx.send(buf).context("send data message")?;
                         }
-                        Err(e) => match Errno::from_raw(e.raw_os_error().context("get OS error")?) {
+                        Err(e) => match Errno::from_i32(e.raw_os_error().context("get OS error")?) {
                             Errno::EIO => {
                                 debug!("Stopping read loop because of IO error");
                                 return Ok(());
diff --git a/conmon-rs/server/src/container_io.rs b/conmon-rs/server/src/container_io.rs
index 19c555ad1e..8118d6e220 100644
--- a/conmon-rs/server/src/container_io.rs
+++ b/conmon-rs/server/src/container_io.rs
@@ -279,7 +279,7 @@ impl ContainerIO {
                     }
                 }
 
-                Err(e) => match Errno::from_raw(e.raw_os_error().context("get OS error")?) {
+                Err(e) => match Errno::from_i32(e.raw_os_error().context("get OS error")?) {
                     Errno::EIO => {
                         debug!("Stopping read loop");
                         attach
diff --git a/conmon-rs/server/src/server.rs b/conmon-rs/server/src/server.rs
index 3d0a0adbff..42eabeff00 100644
--- a/conmon-rs/server/src/server.rs
+++ b/conmon-rs/server/src/server.rs
@@ -19,7 +19,7 @@ use conmon_common::conmon_capnp::conmon::{self, CgroupManager};
 use futures::{AsyncReadExt, FutureExt};
 use getset::Getters;
 use nix::{
-    errno::Errno,
+    errno,
     libc::_exit,
     sys::signal::Signal,
     unistd::{fork, ForkResult},
@@ -123,7 +123,7 @@ impl Server {
 
         // now that we've forked, set self to childreaper
         prctl::set_child_subreaper(true)
-            .map_err(Errno::from_raw)
+            .map_err(errno::from_i32)
             .context("set child subreaper")?;
 
         let enable_tracing = self.config().enable_tracing();
diff --git a/dependencies.yaml b/dependencies.yaml
index bef0f21573..e734af33c8 100644
--- a/dependencies.yaml
+++ b/dependencies.yaml
@@ -11,7 +11,7 @@ dependencies:
         match: GO_VERSION
 
   - name: rust
-    version: 1.75.0
+    version: 1.66.1
     refPaths:
       - path: .github/workflows/ci.yml
         match: ACTION_MSRV_TOOLCHAIN