diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 30580b1..4360bca 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -17,38 +17,50 @@ concurrency:
 
 jobs:
   test:
-    name: Julia ${{ matrix.version }} - ${{ matrix.os }} - ${{ matrix.arch }} - ${{ github.event_name }}
     runs-on: ${{ matrix.os }}
     strategy:
       fail-fast: false
       matrix:
         version:
+          - '1.10'
+          - '1.11'
+          - '1.12'
           - 'nightly'
-          - '1'
-          - '1.9'
         os:
           - ubuntu-latest
           - windows-latest
-        arch:
-          - x64
-          - x86
-        include:
-          - os: macOS-latest
-            arch: aarch64
-            version: '1'
-          - os: macOS-latest
-            arch: aarch64
-            version: 'nightly'
+          - macos-15-intel # Intel
+          - macos-latest # Apple Silicon
+        julia-wordsize:
+          # The value here only affects the version of Julia binary that we download.
+          # It does not affect the architecture of the GitHub Runner (virtual machine) that
+          # we run on.
+          - '32' # 32-bit Julia. Only available on x86_64. Not available on aarch64.
+          - '64' # 64-bit Julia.
         exclude:
-          - os: windows-latest # Killing workers doesn't work on windows in 1.9
-            version: '1.9'
+          # Killing workers doesn't work on Windows in Julia 1.10:
+          - os: windows-latest
+            version: '1.10'
+          # We don't have 32-bit builds of Julia for Intel macOS:
+          - os: macos-15-intel # Intel
+            julia-wordsize: '32'
+          #
+          # We don't have 32-bit builds of Julia for Apple Silicon macOS:
+          - os: macos-latest # Apple Silicon
+            julia-wordsize: '32'
 
     steps:
       - uses: actions/checkout@v6
       - uses: julia-actions/setup-julia@v2
         with:
           version: ${{ matrix.version }}
-          arch: ${{ matrix.arch }}
+          # If `julia-wordsize` is 32, then we set `arch` to `x86`, because we know that
+          # 32-bit builds of Julia are only available for x86.
+          #
+          # If `julia-wordsize` is 64, then we set `arch` to `${{ runner.arch }}`, which
+          # GitHub will automatically expand to the correct value (`x86_64` or `aarch64`)
+          # based on the architecture of the underlying GitHub Runner (virtual machine).
+          arch: ${{ github.ref == '32' && 'x86' || runner.arch }}
       - uses: actions/cache@v5
         env:
           cache-name: cache-artifacts
@@ -60,9 +72,26 @@ jobs:
             ${{ runner.os }}-test-${{ matrix.os }}
             ${{ runner.os }}-
       - uses: julia-actions/julia-buildpkg@v1
+      - name: Decide what the value of JULIA_NUM_THREADS should be
+        id: decide-numthreads-str
+        run: |
+          if Base.VERSION >= v"1.12-"
+              # The x,y format for threadpools requires Julia 1.9 or above.
+              # However, Julia didn't begin starting with 1 interactive thread by default until Julia 1.12
+              # So we don't need to bother with this on Julia 1.11 and earlier
+              value = "1,0"
+          else
+              value = "1"
+          end
+          open(ENV["GITHUB_OUTPUT"], "a") do io
+              name = "numthreads"
+              line = "$(name)=$(value)"
+              println(io, line)
+          end
+        shell: julia --color=yes {0}
       - uses: julia-actions/julia-runtest@v1
         env:
-          JULIA_NUM_THREADS: 4,4
+          JULIA_NUM_THREADS: ${{ steps.decide-numthreads-str.outputs.numthreads }}
       - uses: julia-actions/julia-processcoverage@v1
       - uses: codecov/codecov-action@v5
         with:
diff --git a/test/runtests.jl b/test/runtests.jl
index 0e7441d..bbc8577 100644
--- a/test/runtests.jl
+++ b/test/runtests.jl
@@ -14,6 +14,14 @@ cmd = `$test_exename $test_exeflags`
 if Sys.isunix()
     # Run the SSH tests with a single thread because LibSSH.jl is not thread-safe
     sshtestfile = joinpath(@__DIR__, "sshmanager.jl")
+    if Base.VERSION >= v"1.12-"
+        # The x,y format for threadpools requires Julia 1.9 or above.
+        # However, Julia didn't begin starting with 1 interactive thread by default until Julia 1.12
+        # So we don't need to bother with this on Julia 1.11 and earlier
+        JULIA_NUM_THREADS = "1,0"
+    else
+        JULIA_NUM_THREADS = "1"
+    end
     run(addenv(`$cmd $sshtestfile`, "JULIA_NUM_THREADS" => "1"))
 else
     @warn "Skipping the SSH tests because this platform is not supported"