diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index f8321c8e..69d78953 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -14,7 +14,7 @@ jobs:
 
       - uses: dtolnay/rust-toolchain@master
         with:
-          toolchain: "1.59.0"
+          toolchain: "1.64.0"
 
       - name: version info
         run: rustc --version; cargo --version;
@@ -30,7 +30,7 @@ jobs:
 
       - uses: dtolnay/rust-toolchain@master
         with:
-          toolchain: "1.59.0"
+          toolchain: "1.64.0"
 
       - run: |
           rustup component add rustfmt
@@ -44,7 +44,7 @@ jobs:
 
       - uses: dtolnay/rust-toolchain@master
         with:
-          toolchain: "1.59.0"
+          toolchain: "1.64.0"
 
       - run: |
           rustup component add clippy
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 5f7a63d7..8412b2d9 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,6 +7,12 @@
 
 -->
 
+# 0.13.1
+
+ - update `clap` dependency to 4.x.x to silence `atty` security warning
+ - bump MSRV to 1.64.0 for new `clap` version
+ - fix bug in which `--no-charset` flag wasn't respected
+
 # 0.13.0
 
  - fix various module system bugs when combined with `@import`. this is potentially breaking in rare cases where users were relying on the incorrect behavior
diff --git a/README.md b/README.md
index 179e692b..1658ef75 100644
--- a/README.md
+++ b/README.md
@@ -88,7 +88,7 @@ around comments in expanded mode or error messages.
 
 ## Versioning
 
-The minimum supported rust version (MSRV) of `grass` is `1.59.0`. An increase to the MSRV will correspond with a minor version bump. The current MSRV is not a hard minimum, but future bugfix
+The minimum supported rust version (MSRV) of `grass` is `1.64.0`. An increase to the MSRV will correspond with a minor version bump. The current MSRV is not a hard minimum, but future bugfix
 versions of `grass` are not guaranteed to work on versions prior to this.
 
 `grass` currently targets `dart-sass` version `1.54.3`. An increase to this number will correspond to either a minor or bugfix version bump, depending on the changes.
diff --git a/crates/compiler/Cargo.toml b/crates/compiler/Cargo.toml
index b903b458..a4f8a7bb 100644
--- a/crates/compiler/Cargo.toml
+++ b/crates/compiler/Cargo.toml
@@ -9,6 +9,7 @@ categories = ["web-programming"]
 keywords = ["scss", "sass", "css", "web"]
 repository = "https://github.com/connorskees/grass"
 authors = ["Connor Skees <39542938+ConnorSkees@users.noreply.github.com>"]
+rust-version = "1.64.0"
 
 [lib]
 name = "grass_compiler"
diff --git a/crates/include_sass/Cargo.toml b/crates/include_sass/Cargo.toml
index cc226af3..a285963f 100644
--- a/crates/include_sass/Cargo.toml
+++ b/crates/include_sass/Cargo.toml
@@ -10,6 +10,7 @@ keywords = ["scss", "sass", "css", "web"]
 repository = "https://github.com/connorskees/grass"
 authors = ["Connor Skees <39542938+ConnorSkees@users.noreply.github.com>"]
 include = ["src", "Cargo.toml", "../README.md", "../CHANGELOG.md", "../LICENSE"]
+rust-version = "1.64.0"
 
 [lib]
 proc-macro = true
diff --git a/crates/lib/Cargo.toml b/crates/lib/Cargo.toml
index d06cfc90..dd1ae962 100644
--- a/crates/lib/Cargo.toml
+++ b/crates/lib/Cargo.toml
@@ -11,6 +11,7 @@ authors = ["Connor Skees <39542938+ConnorSkees@users.noreply.github.com>"]
 edition = "2021"
 include = ["src", "Cargo.toml", "README.md", "CHANGELOG.md", "Cargo.lock", "LICENSE"]
 default-run = "grass"
+rust-version = "1.64.0"
 
 [[bin]]
 name = "grass"