diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index b961885ede..838926f5f2 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -112,7 +112,7 @@ jobs:
         run: |
           git clone --depth=50 --branch=master https://github.com/SasView/sasdata.git ../sasdata
           git clone --depth=50 --branch=master https://github.com/SasView/sasmodels.git ../sasmodels
-          git clone --depth=50 --branch=master https://github.com/bumps/bumps.git ../bumps
+          git clone --depth=50 --branch=v0.9.3 https://github.com/bumps/bumps.git ../bumps
 
       - name: Build and install sasdata
         run: |
diff --git a/build_tools/requirements.txt b/build_tools/requirements.txt
index 5bff233141..fab5feb3a4 100644
--- a/build_tools/requirements.txt
+++ b/build_tools/requirements.txt
@@ -1,6 +1,5 @@
 # Alphabetized list of OS and version agnostic dependencies
 appdirs
-bumps
 cffi
 docutils
 dominate
@@ -14,16 +13,19 @@ lxml
 mako
 matplotlib
 numba
+numpy
 periodictable
 pybind11
 pylint
 pyopengl
 pyparsing
+PySide6
 pytest
 pytest_qt
 pytest-mock
 pytools
 qtconsole
+scipy
 six
 sphinx
 superqt
@@ -38,6 +40,4 @@ zope
 pywin32; platform_system == "Windows"
 
 # Alphabetized list of version-pinned packages
-numpy==1.26.4  # 2.0.0 deprecates many functions used in the codebase (and potentially in dependencies)
-PySide6==6.4.3  # Later versions do not mesh well with pyinstaller < 6.0
-scipy==1.13.1  # 1.14 deprecates some functions used in the codebase (and potentially in dependencies)
+bumps==0.*  # v1.+ is very experimental
diff --git a/src/sas/sascalc/fit/BumpsFitting.py b/src/sas/sascalc/fit/BumpsFitting.py
index 985cff3f15..9d75816f8b 100644
--- a/src/sas/sascalc/fit/BumpsFitting.py
+++ b/src/sas/sascalc/fit/BumpsFitting.py
@@ -316,7 +316,14 @@ def fit(self, msg_q=None,
         # Check if uncertainty is missing for any parameter
         uncertainty_warning = False
 
-        for fitness in problem.models:
+        for fitting_module in problem.models:
+            # CRUFT: This makes BumpsFitting compatible with bumps v0.9 and v1.0
+            if isinstance(fitting_module, SasFitness):
+                # Bumps v1.x+ - A Fitness object is returned
+                fitness = fitting_module
+            else:
+                # Bumps v0.x - A module is returned that holds the Fitness object
+                fitness = fitting_module.fitness
             pars = fitness.fitted_pars + fitness.computed_pars
             par_names = fitness.fitted_par_names + fitness.computed_par_names
 
@@ -346,8 +353,8 @@ def fit(self, msg_q=None,
 
            # TODO: Let the GUI decided how to handle success/failure.
             if not fitting_result.success:
-                fitting_result.stderr[:] = np.NaN
-                fitting_result.fitness = np.NaN
+                fitting_result.stderr[:] = np.nan
+                fitting_result.fitness = np.nan
 
             all_results.append(fitting_result)
 
@@ -398,7 +405,7 @@ def abort_test():
     try:
         best, fbest = fitdriver.fit()
     except Exception as exc:
-        best, fbest = None, np.NaN
+        best, fbest = None, np.nan
         errors.extend([str(exc), traceback.format_exc()])
     finally:
         mapper.stop_mapper(fitdriver.mapper)