diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 262bb44..7af7cd8 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -28,7 +28,7 @@ jobs:
     runs-on: ${{ matrix.os }}
     strategy:
       matrix:
-        rust: [1.66.1, stable]
+        rust: [1.59.0, stable]
         os: [ubuntu-latest, macOS-latest, windows-latest]
 
     steps:
@@ -52,7 +52,7 @@ jobs:
     runs-on: ${{ matrix.os }}
     strategy:
       matrix:
-        rust: [1.66.1, stable]
+        rust: [1.59.0, stable]
         os: [ubuntu-latest, macOS-latest, windows-latest]
 
     steps: