diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 7f6b1e7..e87c540 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -68,8 +68,7 @@ jobs:
             rust: nightly
           - os: ubuntu-latest
             # MSRV. Not considered breaking when this has to be bumped.
-            # But should be mentioned in the changelog.
-            rust: 1.64.0
+            rust: 1.70.0
     runs-on: ${{ matrix.os }}
     steps:
       - uses: actions/checkout@v2
diff --git a/Cargo.lock b/Cargo.lock
index 3d821fb..3a452c1 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -224,9 +224,9 @@ dependencies = [
 
 [[package]]
 name = "hermit-abi"
-version = "0.3.1"
+version = "0.3.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "fed44880c466736ef9a5c5b5facefb5ed0785676d0c02d612db14e54f0d84286"
+checksum = "d77f7ec81a6d05a3abb01ab6eb7590f6083d08449fe5a1c8b1e620283546ccb7"
 
 [[package]]
 name = "humantime"
@@ -250,7 +250,7 @@ version = "0.4.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "21b6b32576413a8e69b90e952e4a026476040d81017b80445deda5f2d3921857"
 dependencies = [
- "hermit-abi 0.3.1",
+ "hermit-abi 0.3.3",
  "io-lifetimes",
  "rustix",
  "windows-sys 0.45.0",
@@ -383,9 +383,9 @@ dependencies = [
 
 [[package]]
 name = "proc-macro2"
-version = "1.0.51"
+version = "1.0.67"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "5d727cae5b39d21da60fa540906919ad737832fe0b1c165da3a34d6548c849d6"
+checksum = "3d433d9f1a3e8c1263d9456598b16fec66f4acc9a74dacffd35c7bb09b3a1328"
 dependencies = [
  "unicode-ident",
 ]