diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 73e0108..4cc2d5b 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -51,8 +51,8 @@ jobs:
         set -euo pipefail
 
         # Install the appropriate version of Rust.
-        rustup toolchain install 1.59.0 # [ref:rust_1.59.0]
-        rustup default 1.59.0 # [ref:rust_1.59.0]
+        rustup toolchain install 1.61.0 # [ref:rust_1.61.0]
+        rustup default 1.61.0 # [ref:rust_1.61.0]
 
         # Build and test.
         RUSTFLAGS='--codegen target-feature=+crt-static' cargo build \
@@ -75,8 +75,8 @@ jobs:
         set -euo pipefail
 
         # Install the appropriate version of Rust.
-        rustup toolchain install 1.59.0 # [ref:rust_1.59.0]
-        rustup default 1.59.0 # [ref:rust_1.59.0]
+        rustup toolchain install 1.61.0 # [ref:rust_1.61.0]
+        rustup default 1.61.0 # [ref:rust_1.61.0]
 
         # Build and test.
         cargo build --locked --release --target x86_64-apple-darwin
@@ -135,8 +135,8 @@ jobs:
         set -euo pipefail
 
         # Install the appropriate version of Rust.
-        rustup toolchain install 1.59.0 # [ref:rust_1.59.0]
-        rustup default 1.59.0 # [ref:rust_1.59.0]
+        rustup toolchain install 1.61.0 # [ref:rust_1.61.0]
+        rustup default 1.61.0 # [ref:rust_1.61.0]
 
         # Fetch the program version.
         VERSION="$(cargo pkgid | cut -d# -f2 | cut -d: -f2)"
diff --git a/toast.yml b/toast.yml
index d4f3ab1..e8f0643 100644
--- a/toast.yml
+++ b/toast.yml
@@ -20,7 +20,7 @@ command_prefix: |
   # version for the `trailing_comma` formatting option [tag:rust_fmt_nightly]. The nightly version
   # was chosen as the latest available release with all components present according to this page:
   #   https://rust-lang.github.io/rustup-components-history/x86_64-unknown-linux-gnu.html
-  cargo-fmt () { cargo +nightly-2022-01-16 --frozen --offline fmt --all -- "$@"; }
+  cargo-fmt () { cargo +nightly-2022-05-21 --frozen --offline fmt --all -- "$@"; }
 tasks:
   install_packages:
     description: Install system packages.
@@ -72,10 +72,10 @@ tasks:
       - install_packages
       - create_user
     command: |
-      # Install stable Rust [tag:rust_1.59.0].
+      # Install stable Rust [tag:rust_1.61.0].
       curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh -s -- \
         -y \
-        --default-toolchain 1.59.0 \
+        --default-toolchain 1.61.0 \
         --profile minimal \
         --component clippy
 
@@ -83,7 +83,7 @@ tasks:
       . "$HOME/.cargo/env"
 
       # Install nightly Rust [ref:rust_fmt_nightly].
-      rustup toolchain install nightly-2022-01-16 --profile minimal --component rustfmt
+      rustup toolchain install nightly-2022-05-21 --profile minimal --component rustfmt
 
   install_tools:
     description: Install the tools needed to build and validate the program.