diff --git a/syntaxdot-cli/Cargo.toml b/syntaxdot-cli/Cargo.toml
index 884a5fd..cb41762 100644
--- a/syntaxdot-cli/Cargo.toml
+++ b/syntaxdot-cli/Cargo.toml
@@ -8,6 +8,7 @@ homepage = "https://github.com/tensordot/syntaxdot"
 repository = "https://github.com/tensordot/syntaxdot.git"
 documentation = "https://github.com/tensordot/syntaxdot"
 license = "MIT OR Apache-2.0"
+rust-version = "1.70.0"
 
 [[bin]]
 name = "syntaxdot"
diff --git a/syntaxdot-encoders/Cargo.toml b/syntaxdot-encoders/Cargo.toml
index 83ebe5e..3f38f1a 100644
--- a/syntaxdot-encoders/Cargo.toml
+++ b/syntaxdot-encoders/Cargo.toml
@@ -8,6 +8,7 @@ homepage = "https://github.com/tensordot/syntaxdot"
 repository = "https://github.com/tensordot/syntaxdot.git"
 documentation = "https://docs.rs/syntaxdot-encoders/"
 license = "MIT OR Apache-2.0"
+rust-version = "1.70.0"
 
 [dependencies]
 caseless = "0.2"
diff --git a/syntaxdot-summary/Cargo.toml b/syntaxdot-summary/Cargo.toml
index 9b876a0..3b19dab 100644
--- a/syntaxdot-summary/Cargo.toml
+++ b/syntaxdot-summary/Cargo.toml
@@ -8,6 +8,7 @@ homepage = "https://github.com/tensordot/syntaxdot"
 repository = "https://github.com/tensordot/syntaxdot.git"
 documentation = "https://docs.rs/syntaxdot-transformers/"
 license = "MIT OR Apache-2.0"
+rust-version = "1.70.0"
 
 
 [dependencies]
diff --git a/syntaxdot-tch-ext/Cargo.toml b/syntaxdot-tch-ext/Cargo.toml
index e071ca2..26faeed 100644
--- a/syntaxdot-tch-ext/Cargo.toml
+++ b/syntaxdot-tch-ext/Cargo.toml
@@ -8,6 +8,7 @@ homepage = "https://github.com/tensordot/syntaxdot"
 repository = "https://github.com/tensordot/syntaxdot.git"
 documentation = "https://docs.rs/syntaxdot-tch-ext/"
 license = "MIT OR Apache-2.0"
+rust-version = "1.70.0"
 
 [dependencies]
 itertools = "0.11"
diff --git a/syntaxdot-tokenizers/Cargo.toml b/syntaxdot-tokenizers/Cargo.toml
index f1cbce5..be30742 100644
--- a/syntaxdot-tokenizers/Cargo.toml
+++ b/syntaxdot-tokenizers/Cargo.toml
@@ -8,6 +8,7 @@ homepage = "https://github.com/tensordot/syntaxdot"
 repository = "https://github.com/tensordot/syntaxdot.git"
 documentation = "https://docs.rs/syntaxdot-tokenizers/"
 license = "MIT OR Apache-2.0"
+rust-version = "1.70.0"
 
 [dependencies]
 ndarray = "0.15"
diff --git a/syntaxdot-transformers/Cargo.toml b/syntaxdot-transformers/Cargo.toml
index e3c3bc7..d6015d2 100644
--- a/syntaxdot-transformers/Cargo.toml
+++ b/syntaxdot-transformers/Cargo.toml
@@ -8,6 +8,7 @@ homepage = "https://github.com/tensordot/syntaxdot"
 repository = "https://github.com/tensordot/syntaxdot.git"
 documentation = "https://docs.rs/syntaxdot-transformers/"
 license = "MIT OR Apache-2.0"
+rust-version = "1.70.0"
 
 [dependencies]
 serde = { version = "1", features = ["derive"] }
diff --git a/syntaxdot/Cargo.toml b/syntaxdot/Cargo.toml
index 821a764..78bf737 100644
--- a/syntaxdot/Cargo.toml
+++ b/syntaxdot/Cargo.toml
@@ -8,6 +8,7 @@ homepage = "https://github.com/tensordot/syntaxdot"
 repository = "https://github.com/tensordot/syntaxdot.git"
 documentation = "https://docs.rs/syntaxdot/"
 license = "MIT OR Apache-2.0"
+rust-version = "1.70.0"
 
 [dependencies]
 chu-liu-edmonds = "0.1"