diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index cab85558..81d6ccad 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -22,23 +22,29 @@ jobs:
             cpu: i386
           - os: macos
             cpu: amd64
+          - os: macos
+            cpu: arm64
           - os: windows
             cpu: amd64
-          #- os: windows
-            #cpu: i386
         branch: [version-1-6, version-2-0, devel]
         include:
           - target:
               os: linux
-            builder: ubuntu-20.04
+            builder: ubuntu-latest
             shell: bash
           - target:
               os: macos
-            builder: macos-12
+              cpu: amd64
+            builder: macos-13
+            shell: bash
+          - target:
+              os: macos
+              cpu: arm64
+            builder: macos-latest
             shell: bash
           - target:
               os: windows
-            builder: windows-2019
+            builder: windows-latest
             shell: msys2 {0}
 
     defaults:
@@ -50,7 +56,7 @@ jobs:
     continue-on-error: ${{ matrix.branch == 'devel' }}
     steps:
       - name: Checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
 
       - name: Enable debug verbosity
         if: runner.debug == '1'
@@ -102,7 +108,7 @@ jobs:
       - name: Restore Nim DLLs dependencies (Windows) from cache
         if: runner.os == 'Windows'
         id: windows-dlls-cache
-        uses: actions/cache@v3
+        uses: actions/cache@v4
         with:
           path: external/dlls-${{ matrix.target.cpu }}
           key: 'dlls-${{ matrix.target.cpu }}'
@@ -126,6 +132,8 @@ jobs:
         run: |
           if [[ '${{ matrix.target.cpu }}' == 'amd64' ]]; then
             PLATFORM=x64
+          elif [[ '${{ matrix.target.cpu }}' == 'arm64' ]]; then
+            PLATFORM=arm64
           else
             PLATFORM=x86
           fi
diff --git a/.github/workflows/doc.yml b/.github/workflows/doc.yml
index 5d4022c8..5fc0d524 100644
--- a/.github/workflows/doc.yml
+++ b/.github/workflows/doc.yml
@@ -15,7 +15,7 @@ jobs:
     continue-on-error: true
     steps:
       - name: Checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
         with:
           submodules: true
       - uses: actions-rs/install@v0.1
@@ -41,7 +41,7 @@ jobs:
 
       - uses: jiro4989/setup-nim-action@v1
         with:
-          nim-version: '1.6.16'
+          nim-version: '1.6.20'
 
       - name: Generate doc
         run: |
diff --git a/chronos.nimble b/chronos.nimble
index e8334ceb..a6ae7491 100644
--- a/chronos.nimble
+++ b/chronos.nimble
@@ -55,10 +55,10 @@ task examples, "Build examples":
 
 task test, "Run all tests":
   for args in testArguments:
+    # First run tests with `refc` memory manager.
+    run args & " --mm:refc", "tests/testall"
     if (NimMajor, NimMinor) > (1, 6):
-      # First run tests with `refc` memory manager.
-      run args & " --mm:refc", "tests/testall"
-    run args, "tests/testall"
+      run args & " --mm:orc", "tests/testall"
 
 task test_v3_compat, "Run all tests in v3 compatibility mode":
   for args in testArguments:
@@ -75,10 +75,10 @@ task test_libbacktrace, "test with libbacktrace":
     ]
 
     for args in allArgs:
+      # First run tests with `refc` memory manager.
+      run args & " --mm:refc", "tests/testall"
       if (NimMajor, NimMinor) > (1, 6):
-        # First run tests with `refc` memory manager.
-        run args & " --mm:refc", "tests/testall"
-      run args, "tests/testall"
+        run args & " --mm:orc", "tests/testall"
 
 task docs, "Generate API documentation":
   exec "mdbook build docs"