diff --git a/.github/workflows/macos.yml b/.github/workflows/macos.yml
index f01336da0..fa02854d3 100644
--- a/.github/workflows/macos.yml
+++ b/.github/workflows/macos.yml
@@ -28,11 +28,7 @@ jobs:
         python -m pip install --upgrade pip
     - name: Install Mathics3 with full Python dependencies
       run: |
-        # First install our patched version of stopit
-        git clone --depth 1 https://github.com/Mathics3/stopit.git
-        cd stopit/
-        pip install -e .
-        cd ..
+        python -m pip install -e git+https://github.com/Mathics3/mathics-scanner#egg=Mathics-Scanner[full]
         # We can comment out after next Mathics-Scanner release
         # python -m pip install Mathics-Scanner[full]
         # python -m pip install -e git+https://github.com/Mathics3/mathics-scanner#egg=Mathics-Scanner[full]
diff --git a/.github/workflows/ubuntu-bench.yml b/.github/workflows/ubuntu-bench.yml
index a1b453f46..501629714 100644
--- a/.github/workflows/ubuntu-bench.yml
+++ b/.github/workflows/ubuntu-bench.yml
@@ -25,11 +25,6 @@ jobs:
       run: |
         python -m pip install --upgrade pip
         python -m pip install pytest-benchmark
-        # First install our patched version of stopit
-        git clone --depth 1 https://github.com/Mathics3/stopit.git
-        cd stopit/
-        pip install -e .
-        cd ..
         # We can comment out after next Mathics-Scanner release
         # python -m pip install Mathics-Scanner[full]
         # python -m pip install -e git+https://github.com/Mathics3/mathics-scanner#egg=Mathics-Scanner[full]
diff --git a/.github/workflows/ubuntu-cython.yml b/.github/workflows/ubuntu-cython.yml
index e5f39a9bd..453745833 100644
--- a/.github/workflows/ubuntu-cython.yml
+++ b/.github/workflows/ubuntu-cython.yml
@@ -24,11 +24,6 @@ jobs:
       run: |
         sudo apt-get update -qq && sudo apt-get install -qq liblapack-dev llvm-dev tesseract-ocr
         python -m pip install --upgrade pip
-        # First install our patched version of stopit
-        git clone --depth 1 https://github.com/Mathics3/stopit.git
-        cd stopit/
-        pip install -e .
-        cd ..
         # We can comment out after next Mathics-Scanner release
         # python -m pip install -e git+https://github.com/Mathics3/mathics-scanner#egg=Mathics-Scanner[full]
         pip install -e .
diff --git a/.github/workflows/ubuntu.yml b/.github/workflows/ubuntu.yml
index 0a5bfd939..f5edc3237 100644
--- a/.github/workflows/ubuntu.yml
+++ b/.github/workflows/ubuntu.yml
@@ -24,9 +24,11 @@ jobs:
     - name: Install Mathics3 with full dependencies
       run: |
         python -m pip install --upgrade pip
-        # First install our patched version of stopit
-        git clone --depth 1 https://github.com/Mathics3/stopit.git
-        cd stopit/
+        # We can comment out after next Mathics-Scanner release
+        # python -m pip install -e git+https://github.com/Mathics3/mathics-scanner#egg=Mathics-Scanner[full]
+        git clone --depth 1 https://github.com/Mathics3/mathics-scanner.git
+        # git clone --single-branch --branch operator-refactor-part1.5 https://github.com/Mathics3/mathics-scanner.git
+        cd mathics-scanner/
         pip install -e .
         cd ..
         # We can comment out after next Mathics-Scanner release
diff --git a/.github/workflows/windows.yml b/.github/workflows/windows.yml
index c35ebdd76..640f5e5db 100755
--- a/.github/workflows/windows.yml
+++ b/.github/workflows/windows.yml
@@ -33,11 +33,6 @@ jobs:
         set LLVM_DIR="C:\Program Files\LLVM"
     - name: Install Mathics3 with Python dependencies
       run: |
-        # First install our patched version of stopit
-        git clone --depth 1 https://github.com/Mathics3/stopit.git
-        cd stopit/
-        pip install -e .
-        cd ..
         # We can comment out after next Mathics-Scanner release
         # python -m pip install -e git+https://github.com/Mathics3/mathics-scanner#egg=Mathics-Scanner[full]
         pip install -e .
diff --git a/mathics/builtin/procedural.py b/mathics/builtin/procedural.py
index 6d4841c88..a7e30cfb6 100644
--- a/mathics/builtin/procedural.py
+++ b/mathics/builtin/procedural.py
@@ -529,6 +529,7 @@ def eval(self, n, evaluation: Evaluation):  # pylint: disable=unused-argument
         except ValueError:
             evaluation.message("Pause", "numnm", Expression(SymbolPause, n))
             return
+
         eval_pause(sleep_time, evaluation)
         return SymbolNull
 
diff --git a/mathics/eval/datetime.py b/mathics/eval/datetime.py
index e25cbd4af..8185f2ad2 100644
--- a/mathics/eval/datetime.py
+++ b/mathics/eval/datetime.py
@@ -66,7 +66,7 @@ def eval_pause(sleeptime: float, evaluation):
 
 
 if sys.platform == "emscripten":
-    # from stopit import SignalTimeout as TimeoutHandler
+    # from timed_threads import SignalTimeout as TimeoutHandler
 
     def eval_timeconstrained(
         expr: BaseElement, timeout: float, failexpr: BaseElement, evaluation: Evaluation
@@ -75,7 +75,7 @@ def eval_timeconstrained(
         evaluation.message("TimeConstrained", "tcns")
 
 else:
-    from stopit import ThreadingTimeout as TimeoutHandler
+    from timed_threads import ThreadingTimeout as TimeoutHandler
 
     def eval_timeconstrained(
         expr: BaseElement, timeout: float, failexpr: BaseElement, evaluation: Evaluation
diff --git a/pyproject.toml b/pyproject.toml
index 81d96749d..e5fda4010 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -28,8 +28,8 @@ dependencies = [
     "requests",
     "scipy",
     "setuptools",
-    # stopit is needed in TimeRemaining[]
-    "stopit; platform_system != 'Emscripten'",
+    # Timed-Threads is needed in TimeRemaining[]
+    "Timed-Threads",
     "sympy>=1.13",
 ]
 license = "GPL-3.0-or-later"
diff --git a/test/builtin/test_datentime.py b/test/builtin/test_datentime.py
index 386136d90..3c97ca9cf 100644
--- a/test/builtin/test_datentime.py
+++ b/test/builtin/test_datentime.py
@@ -10,11 +10,15 @@
 import pytest
 
 try:
-    from stopit import __version__ as stopit_version
+    from timed_threads import __version__ as stopit_version
 except ImportError:
-    have_stopit_for_timeconstrained = False
+    have_timed_threads_for_timeconstrained = False
 else:
-    have_stopit_for_timeconstrained = stopit_version.split(".")[:3] >= ["1", "1", "3"]
+    have_timed_threads_for_timeconstrained = stopit_version.split(".")[:3] >= [
+        "1",
+        "1",
+        "3",
+    ]
 
 
 @pytest.mark.skipif(
@@ -154,7 +158,7 @@ def test_private_doctests_datetime(str_expr, msgs, str_expected, fail_msg):
 
 
 @pytest.mark.skipif(
-    sys.platform in ("emscripten",) or not have_stopit_for_timeconstrained,
+    sys.platform in ("emscripten",) or not have_timed_threads_for_timeconstrained,
     reason="TimeConstrained[] is not supported in Pyodide or an unpatched 'stopit'",
 )
 @pytest.mark.parametrize(